Skip to Content


Federal Outer Continental Shelf (OCS) Administrative Boundaries Extending from the Submerged Lands Act Boundary seaward to the Limit of the United States Outer Continental Shelf

Document Details

Information about this document as published in the Federal Register.

Document Statistics
Document page views are updated periodically throughout the day and are cumulative counts for this document including its time on Public Inspection. Counts are subject to sampling, reprocessing and revision (up or down) throughout the day.
Published Document

This document has been published in the Federal Register. Use the PDF linked in the document sidebar for the official electronic format.

Start Preamble


Minerals Management Service (MMS), Interior.


Setting Federal OCS offshore administrative boundaries beyond State submerged lands for Department of the Interior planning, coordination, and administrative purposes.


This notice informs the public that the MMS has developed offshore administrative lines from each adjoining coastal state as described below. Having these lines in place provides various benefits, including:

1. Enhancing the Secretary's ability to ensure that the “4-C's”—communication, consultation and cooperation, all in support of conservation—are considered as she engages in efforts to identify which State has the most interest in the extended area offshore from its coastline because of the increasing number of commercial activities on the Federal OCS, such as permits for liquefied natural gas facilities, wind power, and wave energy;

2. Providing the basis for more accurate delineation of OCS planning areas;

3. Assisting in “affected State” status under the Coastal Zone Management Act and the OCS Lands Act. For example, section 18 of the OCS Lands Act requires the Secretary to consider the “laws, goals, and policies of affected States.” Similarly, section 19 analysis requires the Secretary to balance national interests with the “well-being of the citizens of the affected State”;

4. Providing a more accurate basis for the Secretary to consider support for, or objections to, a State's request to analyze leasing off its shores. Without such administrative lines, it is difficult to define these areas accurately;

5. Assisting in the section 18 comparative analysis to determine “an equitable sharing of developmental benefits and environmental risks among regions.” Such lines will more accurately define the necessary assumptions of what are “regions”; and

6. Helping define appropriate consultation and information sharing with States. For example, section 19(e) authorizes cooperative agreement with affected States for such activities as information sharing, joint planning, review of plans, and environmental monitoring. This is even more important with the recent passage of the Energy Policy Act of 2005 which gave the MMS the authority to permit alternative and renewable energy projects on the OCS. Many of these projects will be located in areas in which the MMS has not recently been active.

Start Further Info


Renee Orr, Chief, Leasing Division, telephone 703-787-1215.

End Further Info End Preamble Start Supplemental Information



The MMS undertook this task in light of the increasing number and type of both traditional and non-traditional energy, alternative energy-related, and other activities on the OCS. Such activities include sand and gravel dredging; liquefied natural gas handling facilities; wind, wave, and current energy generation projects; and mariculture, as well as other innovative uses of the sea, seabed, existing oil and gas operations, and OCS oil and gas infrastructure that may be pursued in the future. Therefore, the MMS believes that it is appropriate to delineate offshore administrative lines at this time.


Over the past two years, the MMS, National Ocean Service, and Department of State have been updating the National Baseline which provides the basis for developing international jurisdictions, such as the Territorial Sea, Contiguous Zone, and Exclusive Economic Zone, as well as a basis for the proposed boundaries seaward of the Submerged Lands Act state waters. We have used, to the extent practicable, the updated National Baseline to derive offshore administrative boundaries in compliance with accepted cartographic practice. The MMS has used the computational software known as CARIS LOTS “Limits and Boundaries.” One of the many features of this software is that it takes a predetermined baseline and determines boundaries for states with an equidistant line for states that are adjacent or a median line for opposite states, based on geodetic calculations. This software was Start Printed Page 128specifically designed to meet international standards for calculating marine boundaries, including United Nations Convention on the Law of the Sea (UNCLOS) requirements.

For this purpose, we applied the widely accepted and long standing principle of equidistance. An equidistance line is one for which every point on the line is equidistant from the nearest points on the baselines being used. The equidistance principle is a methodology that has been endorsed by the UNCLOS treaty, but predates the treaty and has been used by the Supreme Court of the United States, states, and nations to equitably establish boundaries.

Early in its history, the U.S. used equidistance in the Act of 11 February 1805, 2 Stat. 313, that divided public lands by measurements as close as possible to “equidistant from those two corners which stand on the same line.”

International law often refers to equidistance. Article 6 of the 1958 Geneva Convention on the Continental Shelf, ratified by the U.S. Senate on December 4, 1961, states:

Where the same continental shelf is adjacent to the territories of two or more States whose coasts are opposite each other, the boundary of the continental shelf appertaining to such States shall be determined by agreement between them. In the absence of agreement, and unless another boundary line is justified by special circumstances, the boundary is the median line, every point of which is equidistant from the nearest points of the baselines from which the breadth of the territorial sea of each State is measured.

Following U.S. ratification of the 1958 Geneva Convention, the Supreme Court has used equidistance to resolve disputes between states. In Texas v. Louisiana, the Court established a lateral boundary between Texas and Louisiana through the adoption of an equidistant line.

More recently, Congress has recognized the equidistance principle in ratifying a maritime boundary between the U.S. and Mexico for an area in the Gulf of Mexico over 200 miles from each country known as the Western Gap. This was the third treaty between these countries based on the equidistance principle.

The U.S. Baseline Committee has firmly established equidistance as the principle for domestic and international boundaries. The President formed the Committee in 1970 to resolve Federal baseline points from which to establish various jurisdictional and boundary issues, such as Federal/State boundary points and the extent of the territorial sea. The Committee has directed the Department of the Interior and all other agencies to apply this standard in dealings with coastal states and for international purposes.

The utilization of the equidistance principle to draw administrative boundaries within areas that are in purely Federal waters is the best means of achieving accurate, fair, and equitable boundary lines extending from states. These lines will help the Secretary and MMS in a variety of internal planning and extended (4C's) coordination purposes.

The extended equidistant lines extending from adjoining State baselines are depicted on the three maps that follow. More detailed information is available at the following Web site:​ld/​lateral.htm.

Start Signature

Dated: December 22, 2005.

Johnnie Burton,

Director, Minerals Management Service.

End Signature Start Printed Page 129

Start Printed Page 130

Start Printed Page 131

End Supplemental Information


[FR Doc. 05-24659 Filed 12-30-05; 8:45 am]