The contiguous United States, also known as the U.S. mainland, officially referred to as the conterminous United States, consists of the 48 adjoining U.S. states and the District of Columbia of the United States in central North America. The term excludes the only two non-contiguous states and the last two to be admitted to the Union, which are Alaska and Hawaii, and all other offshore insular areas, such as the U.S. territories of American Samoa, Guam, the Northern Mariana Islands, Puerto Rico, and the U.S. Virgin Islands. The colloquial term Lower 48 is also used, especially in relation to Alaska. The term The Mainland is used in Hawaii. The related but distinct term continental United States includes Alaska, which is also in North America, but separated from the 48 states by British Columbia in Canada, but excludes Hawaii and all the insular areas in the Caribbean and the Pacific.
The greatest distance on a great-circle route entirely within the contiguous U.S. is 2,802 miles (4,509 km), coast-to-coast between Florida and Washington state; the greatest north–south line is 1,650 miles (2,660 km). The contiguous United States occupies an area of 3,119,884.69 square miles (8,080,464.3 km). Of this area, 2,959,064.44 square miles (7,663,941.7 km) is actual land, composing 83.65 percent of the country's total land area, and is comparable in size to the area of Australia. Officially, 160,820.25 square miles (416,522.5 km) of the contiguous United States is water area, composing 62.66 percent of the nation's total water area.
