The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territories, 326 Indian reservations, and nine minor outlying islands.[h] At nearly 3.8 million square miles (9.8 million square kilometers), it is the world's third- or fourth-largest country by geographic area.[c] The United States shares land borders with Canada to the north and Mexico to the south as well as maritime borders with the Bahamas, Cuba, Russia, and other countries.[i] With a population of more than 331 million people,[j] it is the third most populous country in the world. The national capital is Washington, D.C., and the most populous city and financial center is New York City.