Urban Area Criteria for Census 2000
Notice Of Final Program Criteria.
This Notice announces the Bureau of the Census' (Census Bureau's) criteria for defining urban and rural territory based on the results of Census 2000. These criteria replace and supersede the 1990 census criteria for defining urban and rural territory. In establishing these criteria, the Census Bureau took into account the comments received regarding the information published in the Federal Register on March 28, 2001 (66 FR 17018) and July 27, 2001 (66 FR 39143), as well as research and investigation conducted by Census Bureau staff. The new criteria appear later in this Notice.
Table of Contents Back to Top
- EFFECTIVE DATE:
- FOR FURTHER INFORMATION CONTACT:
- SUPPLEMENTARY INFORMATION:
- Executive Order 12866
- Regulatory Flexibility Act
- Paperwork Reduction Act
- Summary of Comments Received in Response to the March 28, 2001 (66 FR 17018) and July 27, 2001 (66 FR 39143) Federal Register Notices
- The Census Bureau's Decisions Regarding Recommendations Received From Comments Concerning Changes to the Urban Area Criteria for Census 2000
- A. Grandfathering
- B. Developing a Set of Criteria To Include Whole Functioning Governments in Urban Area Definitions
- C. Recognition of Ferries and Other Transportation Modes To Link Discontiguous Qualifying Areas
- D. Size Criteria for Block Groups
- E. Changing the Distance Allowable for a Hop
- F. Changing the Distance Allowable for a Jump
- G. Changing the Population Density Criteria for Block Groups and Blocks
- Urban Area Criteria for Census 2000
- I. Census 2000 Urbanized Area (UA) and Urban Cluster (UC) Definitions
- II. UA and UC Delineation Process Criteria
- III. Splitting UAs
- A. UA Split Criteria When There Are Separate MAs
- B. UA Split Criteria Within the Same MA or County
- IV. Urban Area Title Criteria
- V. Urban Area Code Criteria
- VI. Urban Area Central Place Criteria
- VII. Urban and Rural Classification
EFFECTIVE DATE: Back to Top
This Notice is effective immediately.
FOR FURTHER INFORMATION CONTACT: Back to Top
Robert Marx, Chief, Geography Division, U.S. Census Bureau, 4700 Silver Hill Road-Stop 7400; Washington, DC 20233-7400, telephone (301) 457-2131, or e-mail at: firstname.lastname@example.org.
SUPPLEMENTARY INFORMATION: Back to Top
The Census Bureau identifies and tabulates data for the urban and rural populations and their associated areas solely for the presentation and comparison of census statistical data. It does not take into account or attempt to anticipate any nonstatistical uses that may be made of these areas or their associated data, nor does it attempt to meet the requirements of such nonstatistical program uses. Nonetheless, the Census Bureau recognizes that some Federal and state agencies are required by law to use Census Bureau-defined urban and rural classifications for allocating program funds, setting program standards, and implementing aspects of their programs. The agencies that make such nonstatistical uses of the areas and data should be aware that the changes to the urban and rural criteria for Census 2000 might affect the implementation of their programs.
If a Federal, state, local, or tribal agency voluntarily uses these urban and rural criteria in a nonstatistical program, it is that agency's responsibility to ensure that the results are appropriate for such use. In considering the appropriateness of such nonstatistical program uses, the Census Bureau urges each agency to consider permitting appropriate modifications of the results of implementing the urban and rural criteria specifically for the purposes of its program. When a program permits such modifications, the Census Bureau urges each agency to use descriptive terminology that clearly identifies the different criteria being applied so as to avoid confusion with the Census Bureau's official urban and rural classifications.
This section of the Notice, among other things, provides a brief synopsis of the public comments the Census Bureau received in response to the March 28, 2001 (66 FR 17018) and July 27, 2001 (66 FR 39143) Federal Register Notices, and the decisions the Census Bureau made in response to the public comments received.
In addition, the Census Bureau plans to announce the determinations of Census 2000 urban and rural territory in the near future. Federal agencies should begin to use the new urban/rural definitions to tabulate and publish statistics when the determinations are announced.
Executive Order 12866 Back to Top
This Notice has been determined to be not significant for purposes of Executive Order 12866.
Regulatory Flexibility Act Back to Top
Even though we gave the public prior notice and an opportunity for public comment, we were not required to do so by Title 5, United States Code (U.S.C.), Section 553, or any other law. Therefore, a Regulatory Flexibility Analysis is not required and has not been prepared (5 U.S.C. 603[a]).
Paperwork Reduction Act Back to Top
This program Notice does not represent a collection of information subject to the requirements of the Paperwork Reduction Act, Title 44, U.S.C., Chapter 35.
Summary of Comments Received in Response to the March 28, 2001 (66 FR 17018) and July 27, 2001 (66 FR 39143) Federal Register Notices Back to Top
The March 28, 2001 Federal Register document provided the proposed criteria and the July 27, 2001 Federal Register document provided further clarification. Both Notices requested comment on the Census Bureau's proposed Urban Area Criteria for Census 2000. In response to the two Notices, the Census Bureau received 142 comment letters. Of that number, 81 comments were received from regional planning and nongovernmental organizations, 24 from municipal and county officials, 22 from Members of Congress, 8 from state government officials, 4 from officials of other federal agencies, and 3 from individuals. Many comment letters addressed more than one topic.
Of the 142 letters, 67 offered comments to the proposed criteria for recognizing uninhabitable areas adjacent to bodies of water (floodplains, marshes, and other wetlands); 37 of these dealt specifically with areas not accommodated in the criteria that respondents believed to be uninhabitable. Of these 37 letters, 22 expressed concern about the area that separates Brunswick City and St. Simons Island, Georgia, and 15 dealt with the area in the vicinity of the St. Francis Levee between West Memphis, Arkansas, and Memphis, Tennessee. The majority of the comments concerned the inability of the proposed criteria to define additional types of areas as “uninhabitable” territory. In particular, respondents commented on the inadequacy of the criteria to define intermittently flooded, uninhabited land adjacent to water bodies as uninhabitable, and thus exempted from the distance measurement when attempting to connect qualifying territory. It was recommended that if these additional types of uninhabitable land areas were included in the criteria, important outlying urban territory would qualify for inclusion in urban areas. Not having this territory included in the urban areas would result in a loss of valuable funding. The remaining comments addressed the criteria that allow a 5 mile jump over uninhabitable area, stating that they would benefit large states and urban areas, but not small states and urban areas.
Ten comments expressed concern that there were no provisions in the criteria to include nonresidential urban land uses, such as airports, industrial parks, and large commercial areas, within urban areas. Comments were received from the Lewiston, Idaho-Clarkston, Washington, area (3); the Dallas-Fort Worth, Texas, area (2); the Reno-Sparks, Nevada, area (2); and one comment each was received from the Indianapolis, Indiana; Paducah, Kentucky-Metropolis, Illinois; and Grand Forks, North Dakota-East Grand Forks, Minnesota, areas. The commentors believed the population density criterion of 500 people per square mile (ppsm) was too high and, therefore, would unfairly exclude the surrounding adjacent nonresidential urban land use areas and what they considered the complete extent of their urbanized area. All comments expressed concern about a possible loss of funding or an inability to expend the funding where the community believed it was needed if there were no way to identify and include nonresidential land use as part of the Urban Area Criteria for Census 2000.
Twenty-seven of the comments questioned elimination of the grandfathering criteria; that is, not automatically retaining in the Census 2000 urban definition territory that had been classified as urban based on the 1990 census. Of those commenting, 16 of the 27 comments were concerned with the Bristol, Tennessee-Bristol, Virginia, area and 5 were concerned with the Ventura County and Orange County areas in California. The remaining 6 letters did not cite a specific area; however, all were similar in that they asserted grandfathering should be retained as part of the Urban Area Criteria for Census 2000. It was believed the elimination of this criterion would cause not only a loss in funding, but, more importantly, a loss of urbanized area status.
There were 26 comments expressing concern about eliminating the provision for including whole functioning governments, particularly incorporated cities, towns, villages, and boroughs. Ten of those commenting were especially concerned about the Bristol, Tennessee-Bristol, Virginia, area and one comment was received regarding the Lewiston, Idaho-Clarkston, Washington, area. Although 15 of the 26 responses did not refer to a specific area, all letters dealing with the elimination of the whole-functioning government criterion were in favor of retaining it as part of the Urban Area Criteria for Census 2000. It was believed that by using corporate limits to include whole governmental units in urban definitions, additional nonresidential urban land use would be included in the urban area definitions, thereby alleviating concerns of loss of funding and loss of urbanized area status.
Coupled with elimination of the grandfathering and the whole-functioning government criteria, 18 additional comments specifically expressed concern regarding the loss of urbanized area status; 11 of these additional comments addressed the governments in the Bristol, Tennessee-Bristol, Virginia area. All 18 favored retention of the grandfathering and the whole-functioning government criteria, as all believed their elimination would result in a loss of urbanized area status.
The Census Bureau received 31 comments regarding the splitting and merging of urban areas; 23 of these expressed concern about splitting urban areas in the vicinity of Los Angeles, California, in particular in Ventura County (the Oxnard-Ventura, Simi Valley, and Thousand Oaks areas) and in Orange County. The comments questioned whether smaller urban areas would retain their individual status or be included in the larger Los Angeles urbanized area. The majority of these comments dealt equally with the loss of funding, loss of data, and loss of urbanized area status. There were no comments in favor of merging existing urbanized areas. It was widely held that the splitting of urbanized areas should occur at metropolitan area boundaries.
Twenty-four comments addressed the overall population density criterion, with the majority agreeing that the population density requirement of 500 ppsm was too high and did not allow for the inclusion of nonresidential urban land use areas adjacent to the urbanized area core. Five comments remarked on the density requirements for military installations; all concerned Vandenberg Air Force Base near Lompoc, California, and stated the population density requirement of 500 ppsm was too high and, therefore, would exclude some blocks that are part of the military installation.
There were 11 commenters who remarked about the 2 square mile size limit criterion for census block groups with qualifying density. The majority of commenters believed that the area size limitation should be larger than 2 square miles or that an area threshold should not be used to determine urban area qualification. The consensus among the commenters was that this criterion was arbitrary and, thus, should be removed.
The enclave and indentation criteria generated 11 comments. Those commenters who wanted the criteria to include nonresidential urban land uses in urban areas believed that the 5 square mile size limit for adding enclaves to urban areas was too small. Other commenters remarked that the 3:1 ratio criterion for including indentations favors large urban areas over small urban areas.
There were 19 comments received regarding the jump and hop criteria. The jump and hop criteria are used to include noncontiguous but qualifying territory within an urban area. The criteria are based on the distance of the connection and overall density or population in the qualifying territory. All 19 agreed that the distance for hops and jumps should be increased to better include nonresidential urban land uses in urban areas.
The Census Bureau received one comment requesting the recognition of ferries and other nonroad transport networks as links to discontiguous qualifying areas. It favored the use of ferries and other nonroad connections for hops and jumps, especially in the West, as some transit systems have ferry service across water bodies or lines tunneling through mountains where the alternate road connections may not meet the hop or jump distance criteria.
The Census Bureau's Decisions Regarding Recommendations Received From Comments Concerning Changes to the Urban Area Criteria for Census 2000 Back to Top
This section of the Notice provides information about the Census Bureau's decisions related to the recommendations and comments received. These decisions benefited greatly from the public participation, which served as a reminder that, although identified for purposes of collecting, tabulating, and publishing federal statistics, the urban areas defined through these standards represent areas in which people reside, work, and spend their lives and to which they attach a considerable amount of pride. In arriving at its decisions, the Census Bureau took into account the comments received regarding the information published in the Federal Register on March 28, 2001 (66 FR 17018) and July 27, 2001 (66 FR 39143), as well as research and investigation conducted by Census Bureau staff.
I. The Census Bureau presents below its decisions on changes that were incorporated into the Urban Area Criteria for Census 2000 in response to the many comments received.
A. The Census Bureau accepted the recommendations to include criteria that define “uninhabitable” territory along major bodies of water. The Census Bureau is changing the proposed criteria to include selected unpopulated blocks adjacent to a road connection where that road connection crosses a substantial water area. In addition, the Census Bureau is replacing the term uninhabitable with the term “exempted” to more clearly define the territories that are in this category: water bodies, uninhabited census blocks adjacent to bridged water bodies, military installations, national parks, and national monuments.
The original uninhabitable criteria, which were more restrictive than in the past, were limited to bodies of water, military installations, national parks, and national monuments. The intent was to make the delineation process as objective and uniform as possible, and because only these four categories of topography and land use were uniform and complete for the Nation in the Census Bureau's TIGER database, they were the only items that the Census Bureau believed it could use as a basis for evaluation.
The Census Bureau decided to rename “uninhabitable” as “exempted,” and to include as exempted those land portions of a hop or jump (defined in Sections II.B. and II.C. of the Urban Area Criteria for Census 2000) where the tabulation blocks on both sides of the road connection have zero population and the road connection crosses at least 1,000 feet of water.
Incorporating this new criterion, which is meant to provide a measurable and objective surrogate to define floodplains and marshlands, will allow the Census Bureau to achieve its goal of being able to apply the criteria uniformly throughout the Nation.
B. The Census Bureau accepted the recommendations to include major airports adjoining or surrounded by qualifying urbanized areas or urban clusters, but the Census Bureau decided not to include commercial or industrial areas.
The Census Bureau decided to include major airports adjoining qualifying urbanized areas (UAs) or urban clusters (UCs) when it was able to obtain a comprehensive database of major airports. The decision was made to include only those airports that, according to 2000 Federal Aviation Administration statistics, had an annual enplanement of at least 10,000 people and, thus, qualified as a primary airport. The research conducted regarding the methodology for determining what boundaries to use for the airports determined that airport inclusion should be by whole census block where at least half the land area of the census block was within the airport.
The Census Bureau believes it is advantageous to include major airports within urban areas because doing so will give a better overall picture of an “urbanized area.” Heavily used airports are considered part of the urban fabric of an area and, most importantly, the Census Bureau was able to obtain a single, reliable database source that its staff could use to apply the criteria objectively.
The Census Bureau determined that it could not include industrial or commercial areas on the fringes of UAs or UCs because it could not find a consistent national database that identifies such areas, as it found for major airports. Thus, the Census Bureau does not have the capability to specifically identify commercial and industrial areas on a uniform and comprehensive basis. The Census Bureau is continuing research to determine some objective and consistent way to address issues involving nonresidential urban land uses for urban area determinations in future censuses.
C. The Census Bureau adopted criteria that would permit the splitting of a UA within the same metropolitan statistical area (MSA) and primary metropolitan statistical area (PMSA), and in counties that are not within an MSA or PMSA, when two areas that each would qualify as a UA have only a point connection or are connected by a hop or a jump.
The Census Bureau determined that it is just as important to recognize the autonomy of areas within a metropolitan area (MA) as it is between two or more MAs. The Census Bureau also determined it would not be realistic to apply the same distance criterion of 3 miles used to split a UA that has qualifying territory in separate MAs as the basis for splitting a UA that is within the same MA or outside any MA. The Census Bureau believes the criteria for splitting a UA within the same MA or outside any MA should be more restrictive to ensure that the splitting is limited to areas that are more likely to be independent and to avoid the splitting of a single large UA into many smaller UAs that are not autonomous.
D. The Census Bureau reevaluated the block population density criterion within a military installation. The Census Bureau revised the final Urban Area Criteria for Census 2000 to treat blocks on a military installation that have a population of 1,000-2,499 the same as blocks that have a population density of 500-999 ppsm. The Census Bureau also decided to treat blocks that have a population of 2,500 or more the same as blocks that have a population density of 1,000 ppsm or greater.
The change in the block density criterion for census blocks within a military installation formally recognizes the special situation that was created in agreement with the Department of Defense regarding the collection and presentation of data about military installations. The block numbering algorithm used by the Census Bureau specified that military installations be identified by using as few block numbers as possible. Blocks that have a large area and significant population were created, but seldom did they meet the minimum criteria for qualification as urban based on population density. Even though the density requirement is consistent, the delineation of military blocks is inconsistent; therefore, the 500 ppsm requirement is being waived for blocks on military installations. To apply these new criteria to other blocks would not be appropriate because the Census Bureau used consistent criteria to define the blocks in areas where external agreements for processing were not a factor.
E. The Census Bureau modified the methodology for the indentation criteria from the 3:1 linear ratio measurement to a 4:1 area ratio measurement; it also clarified the criteria.
The decision to change from the linear ratio of measurement to an area ratio, or “circle method,” of measurement was based on the results of research by Census Bureau staff. The results of the research showed that the “circle method” gives a constant comparative ratio, whereas the linear measurement method does not. It also is more difficult to use the length-to-area measurement in a computer environment, where one must first determine the values of an indentation and then calculate the ratio. The inability to ensure consistent automated results made the proposed indentation criteria less objective.
II. Recommendations and comments were received from the public regarding other issues, and subsequent research by Census Bureau staff determined that changes to the current criteria for some issues would be detrimental to the goals of the program. The Census Bureau has decided that no changes will be made to accommodate the following issues in the Urban Area Criteria for Census 2000.
The goal for Census 2000 is to bring the urban area criteria back to a single set of rules that allow for application of automated processes that yield consistent results rather than to have the areas defined through a process of accretion over time. The Census Bureau is striving to eliminate any subjectivity in these delineations. This can be done only by reexamining areas that qualified as UAs in earlier censuses due to the implementation of different criteria following each of those censuses, the possibility of misinterpretations of the criteria, and the inevitable mistakes made during clerical delineations of the past. The areas that no longer qualify as UAs likely will qualify as UCs for Census 2000.
B. Developing a Set of Criteria To Include Whole Functioning Governments in Urban Area Definitions
The Census Bureau wants to define a continuum of urban territory created objectively and equitably for the entire Nation. To apply these criteria consistently, the use of governmental unit boundaries and criteria designed to include whole functioning governments must be eliminated. The Census Bureau evaluated the geographic characteristics of municipal corporations and found widespread variation as a result of each state's unique set of annexation and incorporation laws. The Census Bureau believes the lack of consistency among state laws for establishing governmental unit boundaries would result in inconsistency in urban area definitions.
C. Recognition of Ferries and Other Transportation Modes To Link Discontiguous Qualifying Areas
There is no consistent database of ferry connections and other transportation networks; therefore, the Census Bureau cannot apply the limited data available consistently.
D. Size Criteria for Block Groups
The Census Bureau included a maximum block group size criterion to avoid adding large sparsely settled territories to urban areas. Census Bureau staff found a significant reduction in the percentage of individual blocks that have a population density greater than 500 ppsm, and a significant increase in the land area of blocks that have a population density less than 500 ppsm, when the size of a block group exceeded two square miles. Based on this research, and with the allowance in the criteria for inclusion of individual blocks that have qualifying density, the Census Bureau determined that it was not necessary to change the block group size criterion.
E. Changing the Distance Allowable for a Hop
The Census Bureau determined, after further research, to retain the proposed length for a hop at a distance of less than or equal to 0.5 mile. Based on empirical review, allowing a longer distance for a hop resulted in a significant number of areas linking to other urban areas that were not perceived as actually being connected.
F. Changing the Distance Allowable for a Jump
The Census Bureau determined, after further research, to retain the proposed increase in length for a jump at greater than 0.5 mile but no more than 2.5 miles (it was 1.5 miles in 1990). Based on empirical review, allowing a longer distance for a jump resulted in a significant number of areas linking to other urban areas that were not perceived as actually being connected. In the case of longer jumps, many of the connections would be eliminated subsequently because a UA would be split to avoid joining autonomous qualifying UAs.
G. Changing the Population Density Criteria for Block Groups and Blocks
The proposed population density requirement of 500 ppsm will remain unchanged. This change in the population density requirement will allow the Census Bureau to take into account government policies requiring green space between developments, lessen the effect of large census block groups and blocks that contain both a developed and undeveloped portion, and because consistent nonresidential land use information is not available, will help to qualify areas that have mixed land use within the same block group or block.
Urban Area Criteria for Census 2000 Back to Top
The following criteria apply to the 50 states, the District of Columbia, Puerto Rico, American Samoa, Guam, the Northern Mariana Islands, and the Virgin Islands of the United States.
I. Census 2000 Urbanized Area (UA) and Urban Cluster (UC) Definitions
For Census 2000, a UA consists of contiguous,  densely settled census block groups (BGs)  and census blocks  that meet minimum population density requirements, along with adjacent densely settled census blocks that together encompass a population of at least 50,000 people.
For Census 2000, a UC consists of contiguous, densely settled census BGs and census blocks that meet minimum population density requirements, along with adjacent densely settled census blocks that together encompass a population of at least 2,500 people, but fewer than 50,000 people.
All criteria based on land area, population, and population density reflect the information contained in the Census Bureau's Topologically Integrated Geographic Encoding and Referencing (TIGER) database (the Census 2000 TIGER/Line file at the time of initial delineation) and the official Census 2000 redistricting data file (the 94 file at the time of initial delineation).
II. UA and UC Delineation Process Criteria
The following criteria are provided in the sequence in which they are used by the Census Bureau in an automated software program, with limited interactive modifications, to delineate the UAs and UCs. The purpose of providing the criteria in sequence and in technical terms is to ensure that others can develop similar software to replicate the Census Bureau's urban area delineations.
A.The Census Bureau initiates its delineation of a potential urban area by delineating a densely settled “Initial Core.” The Initial Core is defined by sequentially including the following qualifying territory:
1. One or more contiguous census BGs that have a total land area less than 2 square miles and a population density of at least 1,000 people per square mile (ppsm)  . NOTE: All calculations of population density include only land; the areas of water contained within census BGs and census blocks are not used to calculate population density.
2. If no qualifying census BG exists, one or more contiguous census blocks that have a population density of at least 1,000 ppsm.
3. One or more census BGs that have a land area less than 2 square miles, a population density of at least 500 ppsm, and are contiguous with the BGs identified by criterion II.A.1.
4. One or more contiguous census blocks, each of which has a population density of at least 500 ppsm, and at least one of which is contiguous with the qualifying census BGs or census blocks identified by criterion II.A.1., II.A.2., or II.A.3.
5. Any enclave of contiguous territory that does not meet the criteria above but that is surrounded by census BGs and census blocks that qualify for inclusion in the initial core by criteria II.A.1. through II.A.4., provided the area of the enclave is not greater than 5 square miles.
B. The Census Bureau continues its delineation of a potential urban area by adding, to all initial cores that have a population of 1,000 or more  , other territory with qualifying density that can be reached using a “hop” connection. That is, from the edge of the initial core, the Census Bureau will define a road connection of no greater than 0.5 mile across land that is not classified as “exempted” territory  and that consists of one or more nonqualifying census blocks that connect the initial core to a contiguous area of census BG(s) and/or census blocks(s) that otherwise qualify based on population density and land area.
1. The territory being added to the initial core using a hop connection, which includes the connecting census block(s), census BG(s), and census block(s) that have a population density of at least 500 ppsm, and any enclave blocks within the connecting block(s) or area with qualifying density, must:
a. Have a combined overall population density of at least 500 ppsm, or
b. Have 1,000 or more total population in the qualifying area being added.
2. When adding qualifying territory to the initial core using a hop connection, the Census Bureau tests the five shortest road connections and:
a. Selects the shortest qualifying road connection that does not exceed 0.5 mile across land that is not classified as “exempted” territory, and
b. Selects the connecting block(s) along that road connection that forms the highest overall population density for the entire area (hop blocks plus qualifying blocks) being added to the initial core.
3. Territory that is added to the initial core by means of a hop connection becomes part of the adjusted initial core. The Census Bureau then determines if there is additional qualifying territory that can be added to the adjusted initial core. All measurements of distance and contiguity to the core are made from the adjusted initial core, not from the original initial core. The Census Bureau continues to add qualifying territory by means of a hop connection, modifies the adjusted initial core to include the added territory, and continues to add more qualifying territory via a hop connection, until no additional territory qualifies to be added via a hop connection.
C. After completing the process that adds all territory to an initial core that can be added via hop connections, those cores that have a population of 1,500 or more, now termed “interim cores,” continue the delineation process by adding qualifying territory via a “jump” connection  .
The determination of jumps starts with the interim core that has the greatest population and continues in descending order of population size of each interim core. Starting from the edge of the interim core, the Census Bureau identifies a road connection of greater than 0.5 mile and no more than 2.5 miles across land that is not classified as “exempted” territory, and that consists of one or more nonqualifying census blocks that connect the interim core to contiguous qualifying territory based on population density, land area, and connections made using the hop criteria.
1. The territory being added to the interim core using a jump connection, including the connecting census block(s), qualifying census BG(s), and census block(s) that have a population density of at least 500 ppsm, and any enclave blocks within the connecting block(s) or territory with qualifying density, must:
a. Have a combined overall population density of at least 500 ppsm, or
b. Have a population of 1,000 or more in the qualifying territory being added.
2. When adding qualifying territory to the interim core using a jump connection, the Census Bureau tests the five shortest road connections and:
a. Selects the shortest qualifying road connection that does not exceed 2.5 miles across land that is not classified as “exempted,” and
b. Selects the connecting block(s) along that road connection that forms the highest overall population density for the entire territory (jump blocks plus qualifying blocks) being added to the interim core.
3. No additional jumps may originate from a qualifying area after the first jump in that direction unless the territory being included as a result of the jump was an interim core with a population of 50,000 or more.
D. After territory has been added to the interim core via jump connections, the Census Bureau again includes additional noncontiguous territory to the adjusted interim core using a hop connection, provided the territory qualifies as defined in the criteria associated with II.B.
E. During all phases in which qualifying territory that is discontiguous to the initial or interim cores is being added to the cores, the Census Bureau adds to the cores any qualifying territory where the hop or jump road connections pass through “exempted” territory.
1. Discontiguous territory is added to the cores using hop or jump connections that cross “exempted” territory, provided that:
a. The road connection is no greater than 5 miles between the core and the qualifying area, and
b. The road connection does not cross more than a total of 2.5 miles of territory not classified as “exempted” (those segments of the road connection where “exempted” territory is not on both sides of the road), and
c. The territory being added meets either the population density criteria or total population criteria specified in Sections II.B.1 and II.C.1.
2. The Census Bureau selects the road connection using the criteria specified in Sections II.B.2 and II.C.2.
3. The Census Bureau considers linkages over exempted territory as a hop connection when the total distance of the road segments, excluding the distance across “exempted” territory, does not exceed 0.5 mile, and as a jump connection when the total distance of the road segments is from 0.5 to 2.5 miles, excluding the distance across “exempted” territory.
F. After all territory has been added to the interim core via jump and hop connections, the Census Bureau adds whole tabulation blocks that approximate the territory of major airports, provided at least one of the blocks that represent the airport is included within or contiguous with the interim core.
G. The Census Bureau then adds to the interim cores territory that constitutes enclaves, provided that:
1. The territory is contiguous, surrounded only by land, and consists of census BGs and census blocks that qualify for inclusion in the interim core, and
a. The area of the enclave is not greater than 5 square miles, or
b. All area of the enclave is more than a straight-line distance of 2.5 miles from a land block that is not part of the interim core, or
2. The territory is contiguous, surrounded by both land consisting of census BGs and census blocks that qualify for inclusion in the interim core, and water, and the linear contiguity of the enclave to the land that is within the interim core is greater than the linear contiguity of the enclave to the water.
H. The Census Bureau then inspects the interim cores and, where necessary, splits the interim cores into separate interim cores for purposes of identifying individual urban areas, following the criteria specified in Section III.
I. Upon completing the separation of interim cores, the Census Bureau completes the delineation of urban areas by identifying and adding territory that qualifies as “indentations.”
1. The Census Bureau examines and qualifies only those potential indentation areas that are within the same interim core, not between separate interim cores.
2. Starting from the outermost part of the potential indentation, the Census Bureau will define a “closure qualification line,” defined as a straight line no more than 1 mile in length, that extends from one point along the edge of the interim core across area that is not within the interim core to another point along the edge of the interim core, with both points on land.
3. The Census Bureau then determines if there are any tabulation blocks that have at least 75 percent of their area within the territory formed between the closure qualification line and the interim core.
4. If there are no blocks that have 75 percent or more of their area within that territory, the potential indentation does not qualify to be added to the interim core.
5. If there are any blocks that have 75 percent or more of their area within the territory formed between the closure qualification line and the interim core, the total area of those blocks that meet or exceed the 75-percent criterion is compared to the area of a circle, the diameter of which is the length of the closure qualification line.
6. Those territories under review that have at least four times the area of the circle qualify as an indentation, and the Census Bureau will add the entire area of all those blocks to the interim core.
7. If the collective area of the indentation blocks is less than four times the area of the circle, the Census Bureau defines a different closure qualification line, if possible, and continues the testing and qualification of the potential indentation until it determines if the potential indentation qualifies or fails.
J. As a result of the urban area delineation process, an incorporated place  or census designated place (CDP)  may be partially within and partially outside an urban area. Any place that is split by an urban area boundary is referred to as an extended place.
III. Splitting UAs
The Census Bureau uses the definition of metropolitan areas (MAs), which include metropolitan statistical areas (MSAs), consolidated metropolitan statistical areas (CMSAs), and primary metropolitan statistical areas (PMSAs), in effect for Census 2000 (those MAs established by the Office of Management and Budget on June 30, 1999) to determine when to define separate contiguous UAs. (Note: UCs are never split to recognize MA boundaries.) After delineating the boundary of each UA, the Census Bureau will examine the relationship between that UA and any MSA, CMSA, or PMSA, using the following criteria to determine if the UA should be split and, if so, where the boundary should be located between the resulting separate UAs.
A. UA Split Criteria When There Are Separate MAs
The Census Bureau splits an initial UA that contains at least 50,000 people in two or more separate MAs when the following conditions exist:
1. The UA has at least 50,000 people in each of at least two different MSAs or PMSAs, and the distance along which their areas are contiguous is less than 3 miles. The split will occur at a location near the MSA or PMSA boundary along which their area of contiguity is less than 3 miles.
2. The UA has at least 50,000 people in each of at least two different CMSAs, and the distance along which their areas are contiguous is less than 3 miles. The split will occur at the CMSA boundary.
B. UA Split Criteria Within the Same MA or County
The Census Bureau splits an initial UA within the same MA, or within a county that is not in an MA, when the following conditions exist:
1. The only connection linking or causing contiguity between areas, each of which has an initial core population of at least 50,000, includes either a hop or jump connection, or
2. The connection between areas, each of which has an initial core population of at least 50,000, is not greater than a point-to-point connection.
In both cases, the split will occur at the point-to-point connection, or at both ends of the hop or jump connection that initially linked the areas into a single UA.
IV. Urban Area Title Criteria
A. For those urban areas that contain an incorporated place that has at least 2,500 people in the urban area:
1. The urban area title includes the name of the incorporated place with the most population within the urban area.
2. As many as two additional incorporated place names may be part of the urban area title, provided that:
a. The incorporated place's urban area population exceeds 250,000 people, or
b. The incorporated place has both an urban area population of at least 2,500, and its urban area population includes at least 2/3 of the population in the most populous incorporated place in the urban area.
B. If the urban area does not contain an incorporated place that has at least 2,500 people in the urban area, the urban area title includes the single entity name  that occurs first from the following list:
1. The nonmilitary CDP having the largest population in the urban area, provided its population in the urban area is at least 2,500.
2. The incorporated place having the largest population in the urban area.
3. The nonmilitary CDP having the largest population in the urban area.
4. The military CDP having the largest population in the urban area.
5. The governmental MCD  having the largest population in the urban area.
6. A local name recognized for the area by the United States Geological Survey's Geographic Names Information System, with preference given to post office names recognized by the United States Postal Service (USPS).
C. The criterion for the sequence of place names in the urban area title consists of the qualifying names in descending order of their official population in the urban area. (If two or more entities that qualify to have their names included in the urban area title have exactly the same population, the total population of each is used to determine the sequence of names; or, if no population data are available, as in Section IV.B.6., the entity names will be listed alphabetically.)
D. The urban area title will include the USPS abbreviation of the name of each state or statistically equivalent entity into which the urban area extends.
1. The order of the state names is the same as the order of the related place names in the urban area title.
2. For urban areas that extend into a state(s) in which no incorporated place, CDP, or MCD name is part of the urban area title, the name(s) of this state(s) is included in the urban area title after the name of the state(s) that includes a place or MCD having its name in the urban area title, in descending order of the state's Census 2000 population within the urban area.
E. If a single place or MCD qualifies as the title of more than one urban area, the largest urban area will use the name of the place or MCD. The smaller urban area will have a title consisting of the place or MCD name and a compass directional (North, South, East, or West) as the smaller urban area relates in direction to the larger urban area. For example, if Allenville is used to title the largest urban area, a smaller urban area also using Allenville in the title that lies south of the larger urban area is titled Allenville South.
F. If any title of an urban area duplicates the title of another urban area within the same state, or uses the name of an incorporated place, CDP, or MCD that is duplicated within a state, the name of the county that has most of the population of the largest place or MCD is appended, in parentheses, after the duplicate place or MCD name for each urban area. If there is no incorporated place, CDP, or MCD name in the urban area title, the name of the county having the greatest population residing in the urban area will be appended to the title. For example, Springfield (Ames County), OH, and Springfield (Jefferson County), OH.
V. Urban Area Code Criteria
The Census Bureau assigns a 5-digit numeric code to each urban area. The code is based on a national alphabetic sequence of all urban area names, and is sequenced by state code or state and county code when urban area names are duplicated.
VI. Urban Area Central Place Criteria
The Census Bureau identifies one or more central places for each urban area (if an incorporated place or CDP exists within the urban area) using the following criteria:
A. Any incorporated place or CDP that has its name in the title of the urban area, and
B. Any other incorporated place or CDP that has a population of 50,000 or more within the urban area.
VII. Urban and Rural Classification
The Census Bureau classifies as urban all population and territory within the boundaries of urban areas.  Conversely, the Census Bureau classifies as rural all population and territory that are not within any urban area.
The Census Bureau does not attempt to classify all bodies of water as being either urban or rural. Those bodies of water that appear in the Census Bureau's TIGER database as area features are included in urban areas only if the water body is included in a land BG or census block classified as urban, or if the water body serves as a connection when performing a hop or a jump. The urban and rural classification is not definitive for other bodies of water because the Census Bureau's definition is not intended to limit other classifications of urban and rural when applied to water area.
Dated: February 27, 2002.
William G. Barron, Jr.,
Acting Director, Bureau of the Census.
[FR Doc. 02-6186 Filed 3-14-02; 8:45 am]
BILLING CODE 3510-07-P
Footnotes Back to Top
1. Contiguity requires at least one point of intersection.Back to Context
2. A census block group is a group of census blocks within a census tract whose numbers begin with the same digit; for example, BG 3 within a census tract includes all census blocks numbered from 3000 to 3999.Back to Context
3. A census block is an area normally bounded by visible features, such as streets, streams, and railroads, and by nonvisible features, such as the boundary of an incorporated place, minor civil division (MCD), county, or other Census 2000 tabulation entity.Back to Context
4. The Census Bureau, in agreement with the Department of Defense, imposed restrictions on the selection of features that could be used as block boundaries within military reservations. This resulted in census blocks within military reservations that contain populations of 1,000 or greater, but with unusually low population densities caused by these restrictions. In recognition of this situation, for purposes of urban area delineation, the Census Bureau treats blocks on military reservations that have a population of 2,500 or more as having a population density of 1,000 ppsm, even if the actual density is less than 1,000 ppsm, and those that have a population of 1,000 to 2,499 as having a population density of 500 ppsm.Back to Context
5. All cores of less than 1,000 population are not selected as the starting point for the delineation of a separate urban area; however, these core areas still are eligible for inclusion in a UA or UC, using subsequent criteria and procedures.Back to Context
6. The Census Bureau defines “exempted” territory as areas in which normal residential development is significantly constrained or not possible due to either topographic or land use reasons. Exempted territory is limited to bodies of water, national parks and monuments, military installations, and those segments of a road connection where the populations of the census blocks on both sides of the road are zero and, additionally, the road connection crosses at least 1,000 feet of water. Because the Census Bureau does not have access to or maintain a comprehensive land use database for the entire United States, Puerto Rico, and the Island Areas, only the aforementioned land use types, which are included in or can be derived from the Census Bureau's TIGER database, will be used when identifying exempted territory.Back to Context
7. All adjusted initial cores of less than 1,500 population are not selected to continue the delineation of a separate urban area; however, these core areas still are eligible for inclusion in an urban area using subsequent criteria and procedures.Back to Context
8. An incorporated place is a governmental unit designated as a city, town (except in New England and Wisconsin), village, city and borough, municipality, or borough (except in New York and Alaska); the term also includes all consolidated cities.Back to Context
9. A CDP is a statistical equivalent of an incorporated place and represents a locally defined named area. CDPs are called communidades and zonas urbanas in Puerto Rico.Back to Context
10. If two or three of the entities being considered for an urban area title have exactly the same population in the urban area, the title will include both (or all three) entity names in the title. If four or more entities being considered for an urban area title have exactly the same population, the total population of each entity (as oppose to its urban population) will determine the three names to be included in the title.Back to Context
11. An MCD is a legal subdivision of a county or statistically equivalent entity. Governmental MCDs exist in Connecticut, Illinois, Indiana, Kansas, Maine, Massachusetts, Michigan, Minnesota, Missouri, Nebraska, New Hampshire, New Jersey, New York, North Dakota, Ohio, Pennsylvania, Rhode Island, South Dakota, Vermont, and Wisconsin.Back to Context
12. The Census Bureau's TIGER database is a centerline file; that is, the line representing each feature (such as a road or a stream that has a very small area) follows the center line of the feature. This criterion is not intended to preclude other application from including the entire area of a feature that the Census Bureau has used as the boundary between urban and rural territory as being either entirely urban or entirely rural.Back to Context