a variety of situations exist, but in general, most countries make the following claims measured from the mean low-tide baseline as described in the 1982 UN Convention on the Law of the Sea: territorial sea - 12 nm, contiguous zone - 24 nm, and exclusive economic zone - 200 nm; additional zones provide for exploitation of continental shelf resources and an exclusive fishing zone; boundary situations with neighboring states prevent many countries from extending their fishing or economic zones to a full 200 nm
Definition: This entry includes the following claims, the definitions of which are excerpted from the United Nations Convention on the Law of the Sea (UNCLOS), which alone contains the full and definitive descriptions:
territorial sea - the sovereignty of a coastal state extends beyond its land territory and internal waters to an adjacent belt of sea, described as the territorial sea in the UNCLOS (Part II); this sovereignty extends to the air space over the territorial sea as well as its underlying seabed and subsoil; every state has the right to establish the breadth of its territorial sea up to a limit not exceeding 12 nautical miles; the normal baseline for measuring the breadth of the territorial sea is the mean low-water line along the coast as marked on large-scale charts officially recognized by the coastal state; where the coasts of two states are opposite or adjacent to each other, neither state is entitled to extend its territorial sea beyond the median line, every point of which is equidistant from the nearest points on the baseline from which the territorial seas of both states are measured; the UNCLOS describes specific rules for archipelagic states.
contiguous zone - according to the UNCLOS (Article 33), this is a zone contiguous to a coastal state's territorial sea, over which it may exercise the control necessary to: prevent infringement of its customs, fiscal, immigration, or sanitary laws and regulations within its territory or territorial sea; punish infringement of the above laws and regulations committed within its territory or territorial sea; the contiguous zone may not extend beyond 24 nautical miles from the baselines from which the breadth of the territorial sea is measured (e.g., the US has claimed a 12-nautical mile contiguous zone in addition to its 12-nautical mile territorial sea); where the coasts of two states are opposite or adjacent to each other, neither state is entitled to extend its contiguous zone beyond the median line, every point of which is equidistant from the nearest points on the baseline from which the contiguous zone of both states are measured.
exclusive economic zone (EEZ) - the UNCLOS (Part V) defines the EEZ as a zone beyond and adjacent to the territorial sea in which a coastal state has: sovereign rights for the purpose of exploring and exploiting, conserving and managing the natural resources, whether living or non-living, of the waters superjacent to the seabed and of the seabed and its subsoil, 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; jurisdiction with regard to the establishment and use of artificial islands, installations, and structures; marine scientific research; the protection and preservation of the marine environment; the outer limit of the exclusive economic zone shall not exceed 200 nautical miles from the baselines from which the breadth of the territorial sea is measured.
continental shelf - the UNCLOS (Article 76) defines the continental shelf of a coastal state as comprising the seabed and subsoil of the submarine areas that extend beyond its territorial sea throughout the natural prolongation of its land territory to the outer edge of the continental margin, or to a distance of 200 nautical miles from the baselines from which the breadth of the territorial sea is measured where the outer edge of the continental margin does not extend up to that distance; the continental margin comprises the submerged prolongation of the landmass of the coastal state, and consists of the seabed and subsoil of the shelf, the slope and the rise; wherever the continental margin extends beyond 200 nautical miles from the baseline, coastal states may extend their claim to a distance not to exceed 350 nautical miles from the baseline or 100 nautical miles from the 2,500-meter isobath, which is a line connecting points of 2,500 meters in depth; it does not include the deep ocean floor with its oceanic ridges or the subsoil thereof.
exclusive fishing zone - while this term is not used in the UNCLOS, some states (e.g., the United Kingdom) have chosen not to claim an EEZ, but rather to claim jurisdiction over the living resources off their coast; in such cases, the term exclusive fishing zone is often used; the breadth of this zone is normally the same as the EEZ or 200 nautical miles.
Source: CIA World Factbook - This page was last updated on December 7, 2019