Three Nautical Mile Limit

The three nautical mile (3 nmi) limit refers to a traditional and now largely obsolete maritime boundary that defined a country's territorial waters, for the purposes of trade regulation and exclusivity, as extending as far as the reach of cannons fired from land. In its place, the Territorial Sea boundary at 12 nmi was established as the international norm by the 1982 United Nations Convention on the Law of the Sea.