Pan American Union Headquarters: This was the first major commission in the careers of architects Paul Philippe Cret and Albert P. Kelsey.

The Pan American Union is the home of the world's oldest international association, founded in 1890 to foster cultural and commercial ties among the Western Hemisphere republics. It serves as a focal point of Washington's diplomatic and cultural activity. The building is widely considered to be among the city's most beautiful Beaux Arts buildings, in addition to being among the first major buildings implementing the McMillan Commission's plans for monumental extension of the Mall.

The construction took place from 1908 to 1910 and was largely funded by philanthropist Andrew Carnegie. The property occupies the former site of the Van Ness Mansion, a commanding location on the Ellipse at Constitution Avenue. Marble facades symbolically blend North and South American expression. Iconographic sculpture, principally by Gutzon Borglum and Isidore Konti, decorates the building, and the stately interiors boast extensive artwork. 

Originally called the Bureau of American Republics, the organization was established at the First International Conference of American States in Washington in 1889-1890. It was renamed the Pan American Union in 1910 and later reorganized as the Secretariat of the Organization of American States in 1948.

This site is featured on the Commemorative Monuments and Memorials of DC tour because it features commemorative sculptures honoring Latin American figures and heroes on its grounds.

DC Inventory: November 8, 1964 (Joint Committee on Landmarks)

National Register: June 4, 1969

National Historic Landmark: January 13, 2021