A land area surrounded by water and remaining above sea level during high tide.
Land areas exposed only during low tide are called low-tide elevations or drying rocks, reefs, or shoals. The existence of islands has generated numerous disputes, centering primarily on the size of the territorial sea surrounding an island and the determination of what state has sovereignty over a particular island. The size of the territorial sea has become an important question affecting fishing rights and the right of unrestricted passage for foreign vessels. Although the territorial sea of an island is usually determined by reference to its coastal baseline, some adjustments have been recognized in the cases of archipelagoes and islands located close to the mainland.
Determination of what state has title to an island has traditionally depended upon an open and continuous assertion of sovereignty over the island, which is usually, but not always, accompanied by physical presence of some representative of the state.