Pennsylvania Avenue National Historic Site, designated in 1965. Located in Washington, D.C., the historic area includes Pennsylvania Avenue between the Capitol and the White House, and surrounding streets. Pennsylvania Avenue was conceived in 1791 by Pierre L’Enfant of France, the architect of the United States capital, as a grand avenue connecting the legislative and executive branches of government. Thomas Jefferson is credited with naming Pennsylvania Avenue. Today, Pennsylvania Avenue is both a principal capital street and the site of marches, protests, and inaugural parades. Historic sites on or near Pennsylvania Avenue include Ford’s Theatre National Historic Site, the Old Post Office Tower, and many federal buildings. Administered by the National Park Service. Area undetermined.