- a federal republic in the northern Western Hemisphere comprising 48 contiguous states, the District of Columbia, Alaska in North America, and Hawaii in the North Pacific, and in some contexts considered along with its five inhabited island territories (Puerto Rico, U.S. Virgin Islands, Guam, North Mariana Islands, American Samoa). Conterminous United States, 3,119,885 square miles (8,080,465 square kilometers); with Alaska and Hawaii, 3,796,742 square miles (9,833,517 square kilometers); all 50 states, the District of Columbia, and the island territories, 3,805,927 square miles (9,857,306 square kilometers) Capital: Washington, D.C. Abbreviations: U.S., US
