https://en.wikipedia.org/wiki/Washington,_D.C.
Washington, D.C., formally the District of Columbia, also known as just Washington or simply D.C., is the capital city and federal district of the United States. It is located on the east bank of the Potomac River, which forms its southwestern and southern border with the U.S. state of Virginia, and it shares a land border with the U.S. state of Maryland on its remaining sides.