The United States of America (USA), commonly known as the United States or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major self-governing territories, 326 Indian reservations, and some minor possessions. At 3.8 million square miles, it is the world's third- or fourth-largest country by total area. With a population of more than 328 million people, it is the third most populous country in the world. The national capital is Washington, D.C., and the most populous city is New York City.