Thomas Fairfax was born about 1726 into the transatlantic Fairfax family, although surviving genealogical references provide limited detail about his exact birthplace and early childhood. He was a son of William Fairfax, a British colonial official and land agent, and William’s first wife, Sarah Walker Fairfax. Through his father he was connected to Thomas, sixth Lord Fairfax of Cameron, proprietor of the vast Northern Neck lands in Virginia. His siblings and half-siblings belonged to a family whose fortunes stretched from Britain and the Bahamas to Massachusetts and Virginia. William Fairfax’s career required repeated movement. He served in the Bahamas and later in New England before settling permanently in Virginia. Thomas therefore grew up within an official and mercantile household accustomed to travel, correspondence, and the administration of imperial property. The family eventually established Belvoir plantation on the Potomac River. Its prosperity rested on land, tobacco, and enslaved labor, while its social position brought the children into contact with colonial officers, merchants, and neighboring planters. As a son of the gentry, Thomas would have received instruction in literacy, arithmetic, Anglican religion, riding, and the manners expected of a young gentleman. The documentary record does not securely identify his teachers or advanced studies. Nor did he live long enough to develop the public career achieved by several relatives. Thomas died in 1746, apparently while still about twenty years old. Because his life ended before he could hold important office, he survives mainly in family records rather than political histories. He was part of the older generation at Belvoir that shaped the upbringing and inheritance of George William Fairfax and other family members who later interacted with George Washington.