Washington, D.C., the national capital, is a federal district that was split from the states of Maryland and Virginia in 1791. Not part of any US state, it used to be in the shape of a square, with the land west of the Potomac River coming from Virginia, and the land east of the river coming from Maryland. In 1846, Virginia took back its part of the land. Some people living in DC want it to become a state, or for Maryland to take back its land, so that they can have the right to vote in Congress.