The U.S. Patent Office building is the third-oldest public building in Washington. Just before the Civil War, the building housed clerical offices and exhibition halls filled with patent models displayed in glass cases. In April 1861, the First Rhode Island Volunteer Infantry, one of the first regiments to respond to Lincoln’s call for 75,000 militia to protect the capital, found temporary quarters here amid the patent models.
For almost two years the building served as a military hospital. Poet Walt Whitman made frequent visits to attend the needs of wounded soldiers. In 1864 the U.S. Sanitary Commission held a successful fair here to raise money for relief efforts, and in 1865 the building was the site of Lincoln’s inaugural ball. In 1968, the Smithsonian opened two museums here, the National Portrait Gallery and the Smithsonian American Art Museum.