The United States of America is a federal republic composed of 50 states, a federal district, five major self-governing territories, and various possessions．The country is located mostly in central North America, bordered by Canada to the north, Mexico to the south, the Pacific Ocean to the west, and the Atlantic Ocean to the east．The official language of the United States is English, and the country is commonly referred to as the United States, the U.S. or America．The country was founded in 1776 with the signing of the Declaration of Independence, and its government is based on a system of checks and balances between the executive, legislative, and judicial branches．The United States is known for its diverse population, cultural and economic influence, and global military presence.