United States of America is a constitutional federal republic composed of fifty states and one federal district. Most of the country is located in central North America, where there are forty-eight contiguous states and Washington D. C., the district capital, between the Pacific and Atlantic Oceans, bordered by Canada to the north and south Mexico.
The current name was established on November 15, 1777, when the Second Continental Congress adopted the Articles of Confederation, which stipulate, "The name of this Confederacy shall be" The United States of America. "The short form, "United States", is also standard. Other common forms include U.S. and U.S. "Columbia", a once popular name for the United States, is derived from the name of Christopher Columbus and still remains in the name of the District of Columbia.
