Once part of a large farm in Seaford, Delaware, this two-story brick mansion was completed about 1860 by William Henry Harrison Ross (1814-1887), a farmer and the 37th governor of Delaware, for his family. The property included 14 enslaved persons who labored on the farm. Ross overtly supported the Confederacy and was suspected of selling arms and medicine to the South. He fled to England in the last years of the Civil War to avoid arrest by federal troops.

The Ross House is a well-preserved example of high-style Italianate architecture, inside and out. Also on the grounds is a reconstructed slave quarter that was long ago moved off-site and used as a residence. It was rediscovered in the late 20th century and moved back to the Ross property for interpretive purposes. This is the only known slave quarter to be identified and documented in Delaware. What was once a property of 1,398 acres is now reduced to the mansion and period outbuildings, which are owned and maintained as a museum by the Seaford Historical Society. The Ross House was added to the National Register of Historic Places in 1977. Ross was a founder of the state agricultural society in 1849 and among the first to begin large-scale peach growing in Sussex County. He was instrumental in bringing the Delaware Railroad into southern Delaware. Trains running daily to Philadelphia bolstered the economy as farmers switched crops from wheat and corn to higher-priced tomatoes, strawberries, peaches, and other perishables. Ironically, it was this same railroad that provided vital transportation from the newly completed station at Bridgeville to points north for Harriet Tubman in 1856, as she guided the enslaved woman “Tilly” to freedom, as illustrated in the account at the Seaford Museum. Research on the persons enslaved by Ross is ongoing, and the known stories, including those of “Amey” and “Zachariah,” are interpreted at the mansion and the reconstructed slave quarter.