Maj. Gen. William S. Harney Summer Home, also known as the Harney Mansion, is a historic home located at Sullivan, Crawford County, Missouri. It was built in 1856, and is a 1 3/4-story, eclectic dwelling constructed of native brown sandstone. The house has a rear wing added between 1869 and 1872. It was the summer home of William S. Harney, who purchased it in 1869.
It is operated as a historic house museum.
It was listed on the National Register of Historic Places in 1984.