Thomas Mann Randolph (1768-1828) shared close ties with the Jefferson family. Randolph's father, also named Thomas Mann Randolph (1741-1793), was Thomas Jefferson's second cousin, and Jefferson and the elder Thomas Mann Randolph spent a significant part of their childhoods together at Tuckahoe after the latter's father died in 1745.
The Randolph-Jefferson family ties were strengthened when the younger Thomas Mann Randolph married Jefferson's eldest daughter Martha in 1790 and built a home at Edgehill near Monticello. Randolph often looked after Jefferson's concerns when Jefferson was absent.
Randolph shared many interests with his father-in-law, including the classics and science. He had been educated at home as a boy and then had attended the College of William and Mary and the University of Edinburgh. Though he did not graduate, Randolph applied his studies to experiment with scientific agriculture and to become a respected botanist. He also pursued a political career that included terms as a Virginia delegate, senator, governor, and congressman.
While in office, Randolph supported Jefferson's policies, but he became estranged from his father-in-law and his own family after returning from service as a colonel in the War of 1812. Randolph's financial and personal affairs continued to deteriorate but he eventually reconciled with his wife and children, all of whom had moved permanently to Monticello upon Jefferson's retirement in 1809. Randolph died at Monticello and was buried in the family cemetery.