The United States of America (USA or U.S.A.), commonly known as the United States (US or U.S.) or America, is a country primarily located in North America, between Canada and Mexico. It is a federation of 50 states, a federal capital district (Washington, D.C.), and 326 Indian reservations. Outside the union of states, it asserts sovereignty over five major unincorporated island territories and various uninhabited islands.[j] The country has the world's third-largest land area,[d] largest maritime exclusive economic zone, and the third-largest population, exceeding 334 million. (Wikipedia)