Washington, D.C., formally the District of Columbia, also known as Washington, the District, or D.C., is the capital city and federal district of the United States. The city is located on the east bank of the Potomac River, which forms its southwestern border with Virginia, and it also borders Maryland to its north and east. The city was named for George Washington, a Founding Father, commanding general of the Continental Army in the American Revolutionary War, and the first President of the United States, and the district is named for Columbia, the female personification of the nation. Washington, D.C. represents the southern point of the Northeast megalopolis, one of the nation's largest and most influential cultural, political, and economic regions that runs along its northeast coast from Boston in the north to Washington, D.C. in the south, and also includes New York City, Philadelphia, and Baltimore. As the seat of the U.S. federal government and several international organizations, the city is an important world political capital. It is one of the most visited cities in the U.S. with over 20 million annual visitors as of 2016. The U.S. constitution provides for a federal district under the exclusive jurisdiction of the U.S. Congress. Washington, D.C. is not a part of any U.S. state and is not one itself. The Residence Act, adopted on July 16, 1790, approved the creation of the capital district along the Potomac River. The city was founded in 1791, and Congress held its first session there in 1800. In 1801, the territory, formerly part of Maryland and Virginia and including the settlements of Georgetown and Alexandria, was officially recognized as the federal district. In 1846, Congress returned the land originally ceded by Virginia, including the city of Alexandria; in 1871, it created a single municipal government for the remaining portion of the district. There have been several unsuccessful efforts to make the city into a state since the 1880s, though a statehood bill passed the House of Representatives in 2021. The city is divided into quadrants, which are centered around the Capitol and include 131 neighborhoods. As of the 2020 census, the city had a population of 689,545, making it the 23rd-most populous city in the U.S. and the third-most populous city in the Mid-Atlantic after New York City and Philadelphia. Commuters from the city's Maryland and Virginia suburbs raise the city's daytime population to more than