Feusier Octagon House, 1858 octagonal residence in Russian Hill, San Francisco, United States

The Feusier Octagon House is a three-story residence on Green Street with a distinctive eight-sided form and mansard-style roof. The building is crowned by a cupola that makes its unusual geometric shape clearly visible from the outside.

George Kenny built the house between 1857 and 1858 at 1067 Green Street, and Louis Feusier bought it from him in 1870. Feusier later added a third story, a mansard roof and a cupola. The building was listed as a San Francisco Designated Landmark on October 1, 1970, and joined the National Register of Historic Places on March 24, 1974.

Louis Feusier, a French immigrant who bought the house in 1870, gave the building its name; it is still known by his surname rather than that of George Kenny, who built it. The house is a private residence, so the eight-sided form and cupola are seen from Green Street, not from inside.

The house sits on Green Street between Leavenworth and Jones Streets and is easily visible from the street. The exterior can be photographed by visitors, but the interior is not open to the public.

Three octagon houses survive in San Francisco: this one, the McElroy Octagon House, and the Marine Exchange Lookout Station at Land's End. The Feusier house was a rental property as of 2018 and was listed for sale in 2021 at US$8.6 million.