The United States of America, colloquially known as the United States, the USA, the US, or simply America; is a sovereign state located in North America. The United States is bordered by Canada to the north and Mexico to the south. Originally a collection of British colonies along the Atlantic Ocean, the US declared their independence on July 4, 1776, resulting in the American Revolutionary War. During the early 1880s, the US expanded to the Pacific Ocean and beyond. Debate over the expansion of slavery into these new territories sparked the American Civil War between 1861 until 1865, becoming one of the bloodiest wars during the 19th Century.