The Ellmore Farmhouse is a two-story, 3,300-square-foot property located on West Ox Road in Herndon, Virginia. The farmhouse was constructed principally of yellow pine in 1891 for Mrs. Mary W. Ellmore and her two children. Members of the Ellmore family occupied the property for more than 50 years, operating a productive dairy farm there through 1945, when the property was sold.
The successive owners continued to operate a dairy farm until selling the farm in 1954. In February 2001, the Fairfax County Park Authority purchased the property for inclusion in Frying Pan Farm Park.
The farmhouse has 12 rooms, one full bath and one half-bath, a one-third basement, and a front porch that has been restored to its original span across the full front of the house. It has central heat, gas and sewer connections, and water is available.