Washington, D.C., formally the District of Columbia, also known as just Washington or just D.C., is the capital city and only federal district of the United States.[9] 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 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,[10] 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.[11] It is one of the most visited cities in the U.S., seeing over 20 million visitors in 2016.