English: Looking northeast at the western intersection of Constitution Avenue NW and Pennsylvania Avenue NW in Washington, D.C., in the United States. Pennsylvania Avenue NW was created at the city's inception. But Constitution Avenue NW did not link with Pennsylvania Avenue NW until 1933, when a portion of a $1.9 million Public Works Administration grant allowed the city to link the two ends of Constitution Avenue NW together at Pennsylvania Avenue NW. The intersection opened on August 17, 1933.

Constitution Avenue NW existed only between 3rd and 15th Streets NW from the city's inception in 1791 to 1871. Between 1871 and 1873, the city covered over the Tiber Creek estuary and built the street on top of it west to Virginia Avenue NW. Between 1881 and 1890, the city dredged the Potomac River and reclaimed the land that now constitutes West Potomac Park (for use as a levee). Constitution Avenue NW was then extended through the park to 23rd Street NW.

When Arlington Memorial Bridge was authorized for construction in 1926, Congress ordered that "B Street" be extended to the Potomac River and widened into a ceremonial gateway for the city. In 1931, Congress changed the name of "B Street" to Constitution Avenue. A granite terrace and small traffic circle was constructed on the shores of the Potomac to form the western terminus of the street.

Constitution Avenue did not extend east past 6th Street NW until the Capitol Plaza Commission approved a proposal in April 1928 to extend it through Senate Park and past the U.S. Capitol grounds to link with the avenue's northeast segment. The city and federal government jointly agreed in December 1932 to fund the street's eastward extension to 1st Street NW, and the Public Works Administration grant finished the link with the northeast segment by December 1933.

In the 1950s, Congress authorized construction of the Theodore Roosevelt Memorial Bridge, and ordered that the bridge connect with Interestate-66 (then being built from the east toward the city). Constitution Avenue NW was torn up and the area restored to parkland west of 23rd Street NW. Raised on-ramps and off-ramps were built through the area to connect the avenue to the bridge. The terrace and traffic circle were not destroyed, however.