Rock Hill Farm, located in the rolling Piedmont landscape of Loudoun County, was built as a Quaker-plan dwelling in 1797—as noted on a date stone found in the building’s gable—by Abner Humphrey, a non-Quaker, slaveholding local farmer. Humphrey appears to be responsible as well for the construction of the circa-1797 Pennsylvania-style barn, a tenant house, smoke­house, and sections of the 19th-century fieldstone fences. Descendants of Humphrey owned Rock Hill Farm until 1947, and the family is responsible for a majority of the post-1797 changes and additions made to the property, including a circa-1873 office/dairy, a corncrib, and a livestock shelter. Still retaining its original interior woodwork, the main dwelling, as well as the barn, testify to the influence of the area’s Quaker architectural and agricultural traditions on non-Quakers. The Rock Hill Farm property is under a conservation easement, ensuring its long-term preservation, and the antebellum buildings contribute to the Unison Battlefield Historic District.