Thomas Gray, one of Stephen F. Austin's Old Three Hundred settlers, was in the Austin colony as early as August 1823, when he voted in the alcalde election at San Felipe de Austin. On August 16, 1824, he and a partner, John H. Moore, received title to a league of land east of the Brazos River in what is now Brazoria County and to a labor of land in what is now Colorado County. Sometime in 1824 he quarreled with Silvestre De León over title to property. In January 1825 Gray indicated his choice of certain leagues on the west side of the Colorado River and was so annoyed by failure to receive them that he asked Austin for a certificate stating that he had no land in the colony. The December 1825 census listed him as a resident of the Colorado District, and the census of March 1826 classified him as a farmer and stock raiser, a widower aged between forty and fifty; at that time his household included three daughters and two servants. In January 1827 he was on a committee to appraise property of Thomas Westfall used in service of the Mexican army. Gray died before June 11, 1827, when John B. Weller, administrator of his estate, offered half a league of his land for sale.
Another Austin colony settler named Thomas Gray arrived in Texas from Georgia in May 1830. He was probably the Thomas Gray who, with John W. Hall, Asa Hoxey, and others, organized the Washington Townsite Company in March 1835. A Thomas Gray fought in the Texas Revolution and received land for it.