In 1887, Rev. Thomas A. Broad began constructing a handsome, two-story sandstone house north of Mason's courthouse square on Comanche Creek. The house was later purchased in 1891 by Edward M. Reynolds, a banker from New York, who hired the German architect Richard Grosse to remodel and enlarge the house. In 1919, the property was sold to Swedish immigrant Oscar Seaquist, after which the family made several improvements to the house. Oscar Seaquist died in 1933, leaving his widow, Ada, to care for the mansion until her death in 1972.
The Seaquist's son and daughter-in-law, Ganer and Clara Seaquist began the first major refurbishment of the house in 1972. Work was completed in the summer of 1973 and for the first time the mansion was opened to the public for tours. It received a Texas State Historical Marker in 1974 and is listed on the National Register of Historic Places. The Seaquist House Foundation purchased the house in January of 2015 and continues to restore the property.