McElroy Octagon House

The McElroy Octagon House, also known as the Colonial Dames Octagon House, is a historic octagonal house now located at 2645 Gough Street at Union Street in the Cow Hollow neighborhood of San Francisco, California. On February 23, 1972, it was added to the National Register of Historic Places. The house is open to the public for tours.
History.
William C. McElroy (?–1869) and his spouse Harriet Shober (1816–1899) bought the lot on Gough Street in 1859. McElroy was a wood miller by trade and he built the house between 1860 and 1861, across the street from its present location. Originally the house was designed with two floors, with four rooms on each floor, and with a winding staircase in the middle of the building. The McElroy family lived in the house until around the 1880s, when the house became a rental property. Daniel O’Connell, a co-founder of the Bohemian Club, was one of the rental tenants. In April 1906, the house was badly damaged during the 1906 Earthquake. By 1909, the house was no longer owned by the McElroy family and it changed ownership many times.
The house was vacant and neglected in 1951 when the National Society of the Colonial Dames of America in California bought it, moved it across the street and began its restoration. The house was restored by University of California, Berkeley's former Dean of Architecture, Warren C. Perry. During the restoration, the original layout of the house was changed so the space would be more functional as an event space. By 1953, the building opened as a museum.
The original location of the house (across the street) has condominiums that were built on the property in 1955.
McElroy Octagon House, Feusier Octagon House, and the Marine Exchange Lookout Station at Land's End are the only three remaining octagon houses in the city.