Lee sold the home to his cousin Francis Lightfoot Lee in 1811, whose daughter auctioned the property in 1839. The next owner was William Swartout, and a succession of owners possessed the home over the next century, including the Haight family. In the 1840s the house expanded again with a new one-story kitchen wing on the west side of the house. In 1957, the Federal Aviation Agency purchased the plantation to be used for what is now Dulles International Airport. The FAA intended to burn the house, but a Special Act of Congress prevented this and required it to be administered by a preservation organization. Today Fairfax County administers the site.
On the National Register for Historic Places (recognized in 1970), and accredited by the American Association of Museums, Sully also includes original outbuildings, representative slave quarter and gardens. Guided tours highlight the early 19th century life of the Richard Bland Lee family, tenant farmers and enslaved African Americans. Programs reflect the history of Fairfax County through the 20th century.
The Museum currently offers several tours. Visitors can take a tour of the Sully Plantation home. The home includes period furniture and the tour gives ample information about the Sully family life. The Museum also offers tours of the grounds which include information about archaeological evidence that has been found in the area. This tour focuses on the lives of enslaved persons who lived on the Plantation.