A gambling ship is a sea vessel of any kind on which gambling takes place. Historically, international waters began just 3 miles (4.8 km) from land in many countries. Gambling ships, like offshore radio stations, would usually be anchored just outside the three-mile limit. When the extent of territorial waters were redefined to 12 nautical miles—approximately 13.8 miles (22.2 km)—maintaining a gambling ship became much more uneconomic. In the United States, some states tried to control the effect of gambling ships through the use of state statutes.