America suddenly grew in size by nearly 400,000 square miles, the reason is baffling

A continental shelf is the submerged edge of a continent. When this shelf extends beyond 200 nautical miles from the coast, it’s called the "extended continental shelf" (ECS), according to the U.S. Extended Continental Shelf Project. International law allows countries to claim their ECS within certain limits. While around 75 countries have defined their ECS boundaries, the U.S. didn’t do so until the end of 2023. In December 2023, the U.S. Department of State announced that the U.S. was expanding its ECS by more than 386,000 square miles—about the size of Egypt or slightly more than two Californias, according to Big Think.

“Like other countries, the United States has exclusive rights to conserve and manage the living and non-living resources of its ECS,” proclaimed the State Department. The department also wrote that the ECS has many resources like corals, crabs, and ‘vital habitats for marine life.’

As the U.S. laid claim to its surrounding ocean territory, former Alaskan lieutenant governor and former chair of the U.S. Arctic Research Commission, Mead Treadwell declared, "America is larger than it was yesterday," in a report published by Alaska Public Media. This extension of American territory is a collaborative work of the National Oceanic and Atmospheric Administration (NOAA), the US Geological Survey, and 12 other agencies who had been gathering geological data to define ECS limits, since 2003, as IFL Science explains.

According to the claim, the US has extended its territory in seven offshore areas including the Arctic, Atlantic (east coast), Bering Sea, Pacific (west coast), Mariana Islands, and two areas in the Gulf of Mexico. Big Think reflects that out of these seven areas, the most important is the Arctic, not only because of its size but also because of its resource potential. As the American landmass expands, its strategic position in terms of global shipping, mining, and fishing will also increase in importance.

However, the legal basis of this claim remains somewhat uncertain, as Treadwell explained to the Wilson Center. To make the definition official, the US has to submit data and reports to the United Nations Convention on Law of the Sea (UNCLOS). However, the US has not ratified UNCLOS due to complex political disagreements (the agreement has been ratified by 168 states and the European Union). Although this creates uncertainty and the possibility of conflict, the likelihood of another country filing counterclaims is low.

As the Wilson Center reports, America’s ECS partially overlaps with ECS areas of Canada, The Bahamas, and Japan. In these areas, it will have to establish maritime boundaries in the future. But in other areas including Cuba, Mexico, and Russia, the US has already created boundaries. Plus, there is no need for a future negotiation with Russia over territorial rights. This is because each country has delineated its continental shelf limits concerning a boundary set by a 1990 agreement between the US and the Union of Soviet Socialist Republics on the Maritime Boundary.