The United States Capitol, often called Capitol Hill, is the seat of the United States Congress, the legislative branch of the U.S. federal government. It sits atop Capitol Hill, at the eastern end of the National Mall in Washington, D.C.. Though not at the geographic center of the Federal District, the Capitol forms the origin point for the District's street-numbering system and the District's four quadrants.

The original building was completed in the year 1800 and was subsequently expanded, particularly with the addition of the massive dome. Like the principal buildings of the executive and judicial branches, the Capitol is built in a distinctiveneoclassical style and has a white exterior. Both its east and west elevations are formally referred to as fronts, though only the east front was intended for the reception of visitors and dignitaries.

In 2014, scaffolding was erected around the dome for a restoration project scheduled to be completed by early 2017.