Article One of the United States Constitution provides for a federal district, distinct from the states, to serve as the permanent national capital. The centers of all three branches of the federal government of the United States are located in the District, as are many of the nation's monuments and museums. Washington, D.C. hosts 172 foreign embassies as well as the headquarters of the World Bank, the International Monetary Fund (IMF), the Organization of American States (OAS), and the Inter-American Development Bank. The headquarters of other institutions such as trade unions, lobbying groups, and professional associations are also located in the District.

The United States Congress has supreme authority over Washington, D.C.; residents of the city therefore have less self-governance than residents of the states. The District has a non-voting at-large Congressional delegate, but no senators. If Washington, D.C. were a state, it would rank last in area (behind Rhode Island), second to last in population (ahead of Wyoming), first in population density, 35th in gross state product, and first in percentage of African Americans, which would make Washington, D.C. a minority-majority state.