McElroy Octagon House

The McElroy Octagon House, also called the Colonial Dames Octagon House, is an eight-sided house in the Cow Hollow neighborhood of San Francisco, California. The wood miller William C. McElroy and his wife Harriet built it between 1860 and 1861, with two floors of four rooms each around a winding central staircase. Damaged in the 1906 earthquake and later a rental and then vacant, it was bought in 1951 by the National Society of the Colonial Dames of America in California, which moved it across the street and restored it, changing the layout so it could serve as an event space. It opened as a museum in 1953. It is a San Francisco Designated Landmark and is listed on the National Register of Historic Places, and it is one of only three remaining octagon buildings in the city.