List of Octagon Houses

This is a list of octagon houses. A large number of octagon houses were built in the United States before the American Civil War, and of these, at least 68 are included on the U.S. National Register of Historic Places (NRHP) and survive to this day.

Of these, six are further designated National Historic Landmarks of the United States: Armour-Stiner House in the Hudson River valley in New York, which is perhaps the only domed octagon house in the world; The Octagon House in Washington, D.C. where President Madison lived after the White House was burnt by the British; Thomas Jefferson's retreat Poplar Forest; May's Folly in Georgia; Samuel Sloan-designed Longwood in Natchez, Mississippi, still unfinished after its construction was halted by the American Civil War; and Waverley, also in Mississippi.

Orson Squire Fowler's 1848 book The Octagon House, A Home for All and his "monumental" four-story, 60 room house built during 1848–1853, Fowler's Folly in Fishkill, New York, provided inspiration for a nation-wide fad. Fifty-nine of the sixty-six pre-Civil War houses on the NRHP were built between 1849 and 1861. It is reported that the owner of the first-built of these, the Rich-Twinn Octagon House in western New York, was impressed by seeing an octagon house in the Hudson River Valley, presumably Fowler's home under construction.

At least one of the houses were used as "stations" sheltering escaped slaves on the Underground Railroad: the Octagon House in Fond du Lac, Wisconsin.

Including post-Civil War constructed houses, there are now at least 84 octagon houses that are listed on the National Register of Historic Places.

Octagon houses were particularly popular in New York State. There were 120 octagon houses in New York State, of which 13 are listed on the National Register and listed below.

In 1958 Carl F. Schmidt published The Octagon Fad which attempted to inventory the Fowler-inspired homes, most of which were built prior to 1915 in North America. However only a small fraction of the total are notable and extant.