http://www.gc.noaa.gov/gcil_maritime.htmlparticularly this:
Exclusive Economic Zone
Each coastal State may claim an Exclusive Economic Zone (EEZ) beyond and adjacent to its territorial sea that extends seaward up to 200 nm (nautical miles) from its baselines (or out to a maritime boundary with another coastal State). Within its EEZ, a coastal State has: (a) sovereign rights for the purpose of exploring, exploiting, conserving and managing natural resources, whether living or 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.
The U.S. claimed a 200 nm EEZ in 1983 (Presidential Proclamation No. 5030 of March 10, 1983). The U.S. EEZ overlaps its 12 nm - 24 nm contiguous zone.
Note: Under certain U.S. fisheries laws, such as the Magnuson-Stevens Fishery Conservation and Management Act, the term EEZ is defined as having an inner boundary that is coterminous with the seaward boundary of each of the coastal states of the U.S. See 16 U.S.C. 1802(11). The seaward boundary of each of the coastal states of the U.S. is landward of the outer boundary of the 12 nm U.S. Territorial Sea, and generally extends seaward from three to nine miles from the baseline. (See below for further information on the Three Nautical Mile Line and the Natural Resources Boundary.)