The United States of America, commonly known as the United States or America, is a country primarily located in North America. It is a federal union of 50 states and a federal capital district, Washington, D.C. The 48 contiguous states border Canada to the north and Mexico to the south, with the State of Alaska in the northwest and the archipelagic State of Hawaii in the Pacific Ocean. The United States also asserts sovereignty over five major island territories and various uninhabited islands. The country has the world's third-largest land area and third-largest population, exceeding 340 million. The U.S. also possesses the world's second-largest exclusive economic zone. Its three largest metropolitan areas are New York, Los Angeles, and Chicago, and its three most populous states are California, Texas, and Florida.