William Whitington, called Billy, and Clem Hill escaped together on June 21, 1815, and their flight was reported in the Washington, D.C., Daily National Intelligencer on June 26, 1815. Clem appears to have been captured, because another runaway advertisement appeared two years later for Clem and his wife Sophy, who ran away in the middle of May 1817. A June 14, 1817, advertisement in the Daily National Intelligencer described Sophy as pregnant and suggested that the couple may have fled toward Annapolis, Maryland, where her enslaved father lived. Advertisements seeking their capture ran for more than a year, and the reward increased from $100 to $500. In 1865, Violetta Sprigg, wife of Samuel, sold Northampton to Dr. John Contee Fairfax, Lord Fairfax, Baron of Cameron. During this period, tenant farming was replacing slavery, and some freed slaves remained at Northampton as tenant farmers. The property continued as a working farm until the 1960s, remained in the Fairfax family until 1959, and was eventually purchased by a developer. Many descendants of Northampton slaves and tenant farmers still live in Prince George's County. Six families trace themselves to a common ancestor, Elizabeth Hawkins, who lived at Northampton during the 1800s and appeared in the 1870 U.S. Census as 25 years old and keeping house. She lived with her husband Robert Hawkins, a 50-year-old farm hand, and their two children, Henrietta, age 4, and Edward, age 2. Elizabeth Hawkins's descendants have helped restore and interpret the slave quarters by assisting archaeology and providing oral histories. Susie Smith, Elizabeth's daughter, lived in the brick quarters in the 1920s and 1930s, and her grandchildren remembered visiting her at Northampton and shared their experiences. These oral histories helped archaeologists learn more about life at Northampton during the 1900s. On September 10, 2008, the Northampton Slave Quarters and Archaeological Park was accepted into the National Park Service's National Underground Railroad Network to Freedom Program, which focuses on enslaved African Americans who sought freedom through escape and adds associated sites and programs to a growing national database on the Underground Railroad.