The Old Post Office, listed on the National Register of Historic Places as the Old Post Office and Clock Tower, is located at 1100 Pennsylvania Avenue, N.W. in Washington, D.C. It is a contributing property to the Pennsylvania Avenue National Historic Site. The building's 315-foot (96-meter) high clock tower houses the "Bells of Congress," and its observation level offers panoramic views of the city and its surroundings. A historic federal office building, it now serves as a hotel.

Pennsylvania Avenue is a primarily diagonal street in Washington, D.C. that connects the United States Capitol with the White House and then crosses northwest Washington, D.C. to Georgetown. Traveling through southeast Washington from the Capitol, it enters Prince George's County, Maryland, and becomes MD Route 4 and then MD Route 717 in Upper Marlboro, and finally Stephanie Roper Highway.