The Octagon House and Museum is located in Washington, DC at 18th St. and New York Ave, NW and is the oldest museum in the U.S. dedicated to architecture and design. The Octagon House was designed by Dr. William Thorton (who also designed the U.S. Capitol) and is an example of Federal period architecture. Oddly enough, the house is not shaped like an octagon, and no one is really sure how it got its name. However, the American Architectural Foundation notes on its website that, "One possibility comes from the round entrance hall. In the 18th century, round rooms were often constructed with eight angled walls plastered smooth and were called "octagon salons." Another clue is found in period dictionaries, which define an octagon shape as having eight angles rather than eight sides."
The Octagon House has a place in presidential history as it once served as the temporary residence of President and Mrs. Madison after the British burned the White House. It was in the circular room that the Treaty of Ghent was signed.
The house underwent extensive renovations from 1990 to 1995 and is open to prearranged group tours only. To arrange a tour, call 202-638-3221 or visit the American Architectural Foundation website.
The closest metro stop is Farragut West. Street parking can be tough in the area depending on the time and day of the week you arrange your tour.