Free US Law Dictionary

Territorial Waters

Territorial waters, or a territorial sea, as defined by the 1982 United Nations Convention on the Law of the Sea[1], is a belt of coastal waters extending at most twelve nautical miles from the baseline (usually the mean low-water mark) of a coastal state. The territorial sea is regarded as the sovereign territory of the state, although foreign ships (both military and civilian) are allowed innocent passage through it; this sovereignty also extends to the airspace over and seabed below.

The term "territorial waters" is also sometimes used informally to describe any area of water over which a state has jurisdiction, including also internal waters, the contiguous zone, the exclusive economic zone and potentially the continental shelf.