The United States wasn't always independent.
The United States of America ( USA ) , commonly known as the United States ( U.S. ) or America , is a constitutional federal republic composed of 50 states , a federal district , five major self-governing territories , and various possessions . The United States emerged from 13 British colonies along the East Coast . On July 4 , 1776 , during the course of the American Revolutionary War , the colonies unanimously adopted the Declaration of Independence .