The United States of America is a country located in North America, with a total area of 9,518,900 km², ranking fourth in the world in terms of territory. It has a population of more than 309 million people, ranking third in the world. The capital is Washington. The USA shares borders with Canada, Mexico, and Russia, and is bordered by the Pacific Ocean and the Atlantic Ocean. It consists of 50 states and the federal district of Columbia, as well as several island territories. The USA was formed in 1776 through the union of thirteen British colonies that declared independence.