Washington, D.C., formally the District of Columbia and commonly referred to as Washington or D.C., is the capital of the United States of America. Founded after the American Revolution as the seat of government of the newly independent country, Washington was named after George Washington, first President of the United States and Founding Father. Washington is the principal city of the Washington metropolitan area, which has a population of 6,131,977. Washington has been described as an important political capital, owing to its status as the seat of the United States federal government. Washington is one of the most visited cities in the world, with more than 20 million annual tourists.

The signing of the Residence Act on July 16, 1790, approved the creation of a capital district located along the Potomac River on the country's East Coast. The U.S. Constitution provided for a federal district under the exclusive jurisdiction of the Congress and the District is therefore not a part of any state. The states of Maryland and Virginia each donated land to form the federal district, which included the pre-existing settlements of Georgetown and Alexandria. Named in honor of President George Washington, the City of Washington was founded in 1791 to serve as the new national capital. In 1846, Congress returned the land originally ceded by Virginia; in 1871, it created a single municipal government for the remaining portion of the District.  Source: Wikipedia