Dr. Thomas Walker (1715–1794), a physician, merchant, land speculator, experienced explorer, and storekeeper in Fredericksburg. Walker had extensive landholdings and business interests throughout Virginia, but by June 1756 he seems to have been settled at Castle Hill in the Southwest Mountains of Albemarle County. This was part of a vast estate which had come under Walker’s control by his marriage in 1741 to Mildred Thornton Meriwether, widow of Nicholas Meriwether. Part of the house now standing was built by Walker in 1765, but there was undoubtedly an earlier house somewhere on the tract.