Decatur House was completed in 1819 for Stephen Decatur Jr., one of the most celebrated naval officers of the young republic. Decatur had won fame fighting the Barbary pirates and earned a small fortune in prize money during the War of 1812. He commissioned Benjamin Henry Latrobe -- the neoclassical architect who also designed portions of the Capitol -- to build a Federal-style residence on the most prestigious square in the capital, directly facing the White House. The house is one of only three surviving Latrobe-designed residences in the country. Decatur and his wife Susan barely had time to settle in. In March 1820, just fourteen months after moving in, Decatur was killed in a duel with Commodore James Barron at the Bladensburg dueling grounds. Susan Decatur was left with the house and a legacy of grief.

After Susan Decatur began renting the house, it became something remarkable: the unofficial residence of the Secretary of State. Henry Clay moved in during 1827, followed by Martin Van Buren and then Edward Livingston, each renting the house while serving as the nation's top diplomat. For six consecutive years, from 1827 to 1833, whoever occupied Decatur House also shaped American foreign policy. The proximity to the White House made it the ideal base for late-night consultations and political maneuvering. Cabinet members, senators, and foreign ambassadors became regular visitors. After the secretaries of state departed, the house continued to attract power: Vice President George M. Dallas, Speaker of the House James Lawrence Orr, and Senator Judah Benjamin all called it home at various points before the Civil War.

In 1836, John Gadsby, then the wealthiest man in Washington, moved into Decatur House with his wife Providence and their enslaved household staff. The Gadsbys constructed a two-story structure at the rear of the property to serve as a kitchen and slave quarters. That structure still stands -- one of the few surviving examples of urban slave quarters in the United States and one of the only physical remnants of the fact that African Americans were held in bondage within direct sight of the White House. Charlotte Dupuy's 1829 lawsuit against Henry Clay, filed while she was enslaved in this very house, is now a centerpiece of the museum's interpretation. Today, a special exhibit traces African American history from the era of slavery through 1965, transforming what was once a site of oppression into a place of remembrance and education.

The house sat empty for six years after the Civil War, during which it had served as Army offices. In 1872, Edward Fitzgerald Beale purchased it. Beale was a remarkable figure in his own right -- a frontiersman, explorer, rancher, and diplomat who had once carried gold-rush dispatches across the continent. He and his family filled the house with artifacts from the American West and transformed its upper floors. Beale's daughter-in-law, Marie, eventually bequeathed Decatur House to the National Trust for Historic Preservation in 1956. It was designated a U.S. National Historic Landmark in 1976. Today the lower floor preserves the character of the early nineteenth century, while the upper floor reflects the early twentieth-century renovations. The building also houses the National Center for White House History, operated by the White House Historical Association, anchoring Decatur House firmly in the ongoing story of the presidency it has watched from across the square for more than two hundred years.