An official website of the United States Government Here's how you know

Official websites use .gov

A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS

A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Why delineate the U.S. ECS limits?

The United States, like other countries, has an inherent interest in knowing, and declaring to others, the exact extent of its ECS and thus the sovereign rights it is entitled to exercise in this part of the ocean. Defining those limits in concrete geographical terms will provide the specificity and certainty necessary to protect, manage, and use the resources of the ECS. The collection and analysis of the data necessary to establish the outer limits of the U.S. ECS also provides a better scientific understanding of our continental margins.

What’s down there?

Because most of the ocean — especially the deep ocean — is unexplored, we are unsure exactly what the seafloor looks like or what resources it contains. Mapping and exploring these deep-sea areas will be important to gaining a better understanding of the habitats and resources of the U.S. ECS.

How big is the U.S. ECS?

The U.S. ECS is approximately one million square kilometers — an area about twice the size of California. This is a significant area over which the United States may exercise sovereign rights over seafloor and sub-seafloor resources.

Where is the U.S. ECS?

The United States has ECS in seven offshore areas (Figure 1): the Arctic, Atlantic (east coast), Bering Sea, Pacific (west coast), Mariana Islands, and two areas in the Gulf of Mexico.

The United States may also have ECS in other areas, and the U.S. ECS Project continues to analyze available data and undertake analysis in a range of areas.

Figure 1: U.S. Extended Continental Shelf Regions.

U.S. Department of State

The Lessons of 1989: Freedom and Our Future