The Octagon House is at 1799 New York Avenue. It was built in the Federal style in 1801 for Colonel John Tayloe III, who was a rich Virginia landowner. Tayloe was a friend of George Washington, who convinced him to build the house as a winter residence.
Tayloe saved the house during the War of 1812 by asking the French to assume it as their embassy. In 1814, he lent it to the Madisons to live in after the White House had been burned down. President Madison signed the Treaty of Ghent ending the War of 1812 in the house. In 1899, the American Institute of Architects acquired the house as its headquarters.
The house was designed by William Thornton, who was the original architect of the U.S. Capitol. It is one of the few remaining houses in D.C. from the early Federal period.