United States, officially United States of America, republic (2005 est. pop. 295,734,000), 3,539,227 sq mi (9,166,598 sq km), North America. The United States is the world's third largest country in population and in area. It consists of 50 states and a federal district. The conterminous (excluding Alaska and Hawaii) United States stretches across central North America from the Atlantic Ocean on the east to the Pacific Ocean on the west, and from Canada on the north to Mexico and the Gulf of Mexico on the south. The state of Alaska is located in extreme NW North America between the Arctic and Pacific oceans and is bordered by Canada on the east. The state of Hawaii, an island chain, is situated in the E central Pacific Ocean c.2,100 mi (3,400 km) SW of San Francisco. Washington, D.C., is the capital of the United States, and New York is its largest city.