Thornton was born to a prominent Virginia family with substantial land and slave holdings and diverse business interests in their native state including, blast furnaces, grist mills, lumber mills, ships and commercial enterprises. The first of his ancestors, William Thornton, had arrived in America sometime before 1649, and established large land holdings in
Gloucester County, Virginia, but eventually passed the property on to his son William before his death and his lands in Richmond County to his son Rowland and moved to modern day
Stafford County, Virginia, with his son Francis. This move established Thornton's family and their wealth around the Fredericksburg area. Over time, the family estates were divided among more and more branches which diminished the individual wealth of family members but maintained their overall economic and political strength. Their marriages and familial connections brought three Presidents into his family
George Washington,
James Madison and
Zachary Taylor. Though many had improved their positions through advantageous marriage, it is likely that Thornton and his brother were more prudent in seeking to establish themselves in the booming cotton regions. Thornton's first marriage was to Mary Ann Glover (1808 - 1830), a native of Alabama who was the daughter of Allen Glover and Sarah Norwood. The Glovers had been a moderately affluent South Carolina family who, by the time of Thornton's marriage, had acquired vast land and slave holdings. Glover died within five years of their marriage and Thornton returned to Fredericksburg in 1830 and married his former neighbor and kinsman Anne Amelia Smith, the daughter of George Alexander Smith and Delia Forbes. Smith was connected to the Innes family through their Scottish lines and both of her parents were from prominent Scottish families descended from the Erskines of Alva and Aloa. Smith's brother,
Murray Forbes Smith, brought great economic backing to Thornton through his cotton brokerage set up in
Mobile. Through Smith, Thornton was the uncle of
Alva Vanderbilt Belmont. Thornton's last marriage was to Sarah Williams Gould, the daughter William Proctor Gould and Eliza Williams Chotard. She was the widow of Samuel Merritt Gowdey. Sarah Gould Thornton outlived her husband, dying in 1885. Children by Mary Amelia Glover • Mary Thornton Children by Anne Amelia Smith • George Francis Thornton, • Jean Stirling Thornton • Delia Forbes Smith Thornton • James Innes Thornton Jr. • Fitzgerald Thornton • Katherine Marshall Thornton • Innes Thornton • Butler Brayne Thornton • Harry Innes Thornton Thornton and Sarah Williams Gould had no children. ==Ancestry==