Thomas Valentine Alley, one of Stephen F. Austin's Old Three Hundred colonists, was born in 1798 in Missouri to Catherine (Baker) and Thomas Alley. He left Missouri in the spring of 1822 with his brothers, Abraham and John C. Alley. Carrying letters and supplies for Austin, he and his brothers arrived at Galveston by way of New Orleans on the schooner James Lawrence and traveled to the Atascosito Crossing of the Colorado River where other members of the Alley family settled. Alley posted a $500 bond as constable of the Colorado District in January 1824; he and his brother William A. Alley, Jr., received title to a league of land now in Brazoria County on July 29, 1824. The Austin colony census of 1826 listed Thomas Alley as a farmer, single and aged between twenty-five and forty. During the spring of 1826, while on a campaign against the Waco and Tonkawa Indians, Alley was crossing the Brazos River near the San Antonio Road when he fell from his horse and drowned.
Another Thomas Alley served as a captain in the army of Texan volunteers at the siege of Bexar in 1835.