Washington, D.C. (Wikipedia) 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. The city was named for George Washington, a Founding Father and the first president of the United States, and the federal district is named after Columbia, a female personification of the nation. 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 visitors as of 2016.