The United States, pursuant to international treaties and customary law, has established maritime zones in which various activities are controlled or restricted.  NOAA is responsible for depicting on its nautical charts the limits of the 12 nautical mile Territorial Sea, 24 nautical mile Contiguous Zone, and 200 nautical mile Exclusive Economic Zone (EEZ).  Each of these maritime zones is projected from what is called a “normal baseline,” which is derived from NOAA nautical charts.  A “normal baseline” as defined in the 1958 Geneva Convention on the Territorial Sea and the Contiguous Zone and Article 5 of the United Nations Convention on the Law of the Sea is defined as the low-water line along the coast as marked on officially recognized, large-scale charts.  Since "low-water line" does not reference a specific tidal datum, the U.S. applies the term to reference the lowest charted datum, which is mean lower low water (MLLW) in the U.S. 

The Exclusive Economic Zone (EEZ) of the U.S. extends 200 nm from the territorial sea baseline and is adjacent to the 12 nm territorial sea of the U.S., including the Commonwealth of Puerto Rico, Guam, American Samoa, the U.S. Virgin Islands, the Commonwealth of the Northern Mariana Islands, and any other territory or possession over which the United States exercises sovereignty.  Within the EEZ, the U.S. has (a) sovereign rights for the purpose of exploring, exploiting, conserving and managing natural resources, whether living and nonliving, of the seabed and subsoil and the superjacent waters and with regard to other activities for the economic exploitation and exploration of the zone, such as the production of energy from the water, currents and winds; (b) jurisdiction as provided for in international law with regard to the establishment and use of artificial islands, installations, and structures, marine scientific research, and the protection and preservation of the marine environment, and (c) other rights and duties provided for under international law.  (See Presidential Proclamation No. 5030 of March 10, 1983.)

Note: Under certain U.S. fisheries laws, the term “exclusive economic zone” (“EEZ”) is used. While its outer limit is the same as the EEZ on NOAA charts, the inner limit generally extends landward to the seaward boundary of the coastal states of the U.S.