Block Island was an island of the mainland state of Rhode Island in the United States. It is located 13 miles off the coast of the US state that was practically obliterated in the events of September 25, 1983. Only 9.734 sq mi in land mass, it was home to between 500 and a thousand people in the 1980's. In 2010, its population is estimated to be 500 people, but in claiming a full ten miles from the center of the island as territorial waters, the island has an area of 314.6 sq mi.