The William Strong House was built in 1879 by William Strong, a banker and businessman in Spring Valley. Strong was a native of Pennsylvania who relocated to Minnesota. When the house was being built, it was proclaimed, "the handsomest private ediface in the county" and cost an estimated $8,000. Strong lived here with his wife, Phoebe, and their adopted daughter Hannah. The house was built in the Second Empire style, which is characterized by a "mansard" roof line (named after the 17th century French architect Francois Mansart), dormer windows, and villa-like towers. This was a dominant style for homes constructed between 1860 and 1880, particularly in the Northeastern and Midwestern states. It was considered a very modern style and imitated the latest building style in France; it spread to the United States after the Paris Exhibition in 1855.

The Strong estate originally included the house, several livestock barns, a carriage shed with a turntable (used for turning a carriage around without having to back it up), and even a racetrack. The original house stood until 1894, when a tornado ripped through Spring Valley and took the roof of the house with it. The house was repaired, and an addition built onto the back. The house remained in the Strong family until 1944, after which it served as a doctor's office, a hotel, and a retirement home before being purchased in 1969 for use as a single family dwelling.

Since 1969 the house has been painstakingly restored to its original condition. In 1982, the house and cob barn were named to the National Register of Historic Places; the house was certified as 95% original.