Notable in the development of the law of the sea are two international conventions signed in the latter half of the 20th Century. One, the United Nations Convention on the Territorial Sea and the Contiguous Zone (1958), outlined the rights and responsibilities of States parties in their offshore waters. In 1982, the United Nations Convention on the Law of the Sea further outlined the role of States parties in their marine areas and beyond.
While the United States ratified the 1958 Convention, as of mid-2012, it has not become a party to the 1982 Law of the Sea Convention. The United States recognizes that many of the principles in the 1982 Convention reflect customary international law; however, the U.S. is not bound by the agreement itself.
NOAA has a unique role in administering the law of the sea: Its nautical charts provide the scientifically derived baseline that marks the inner limit of the territorial sea and the outer limit of internal waters, such as bays and rivers. This determines where U.S. territorial waters begin for purposes of international law. The method of arriving at this baseline is described in the 1958 Convention and in the 1982 Convention.
The baselines, and thus the bounds, of offshore marine areas subject to jurisdiction are subject to ongoing revision due to shoreline changes such as accretion (addition of land) and erosion.
The location of maritime boundaries can have potentially far-reaching effects. As a result, NOAA works with other federal agencies, particularly the U.S. Department of State, to keep track of U.S. maritime boundaries and to represent such boundaries, where applicable, on U.S. navigational charts.