William S. Mabry, surveyor, was born near Selma, Alabama, in 1851. He graduated from Virginia Military Institute in July 1871 and in 1872 worked as a rod man with a surveying crew for the Selma, Marion and Memphis Railroad near Holly Springs, Mississippi. When financial difficulties forced the company to suspend work, Mabry, through the influence of John H. Morgan, an old college classmate, accepted a position as chain man for a surveying outfit in Texas. After arriving at Austin, Mabry and William Nelson went to Fort Concho in February 1873 to locate 4,000 land certificates for the Houston and Great Northern Railroad. Operating from that frontier outpost, Mabry and his companions made several surveying expeditions over West Texas and into New Mexico and the Indian Territory; they encountered buffalo and risked Indian attacks. Mabry kept a personal record of his experiences and the surveys his party made during 1873.
After a brief visit to his home in Alabama in 1874, he was appointed a special deputy surveyor at Jacksboro, where he worked under W. A. Benson for two years. During that time he had charge of the surveyor's office, from which crews made numerous surveys of the West Texas plains. In 1882 Mabry was appointed surveyor of the Oldham County Land District and established his office in Tascosa. He was among those who sought unsuccessfully to get a railroad line built through Tascosa. Nevertheless, the Tascosa Pioneer praised him for his "indomitable energy and perseverance," and one of the town's main streets, Mabry Avenue, was named for him.
Since the Oldham County Land District was in the heart of the three million acres the state traded for its new Capitol, Col. Amos C. Babcock of the Capitol Freehold Land and Investment Company enlisted Mabry to help him resurvey it. The party inspected the entire tract, starting from the northwest corner of the state, using a transcript of John H. Clark's 1859 field notes made of each league. The result was the Capitol Syndicate's decision to fence and stock the entire acreage. Mabry's next major task came in 1884, when he was sent to Buffalo Spring, the XIT Ranch's first headquarters, to survey the fence line for a horse pasture and set a stake every thirty feet. Since there was not a stake within miles of the place, Mabry persuaded Bill Metcalf, the local company representative, to let him make a mound of dirt instead of a stake. Even then, the frozen ground often compelled the mound builder to use a pick instead of a spade. Nevertheless, Mabry saw to it that the four-wire pasture fence was completed by the spring of 1885, in time to receive 20,000 cattle that were driven up from South Texas.
Mabry remained with the XIT to conduct subsequent fence line surveys for several years. In 1891, while writing a letter at the general headquarters in Channing, he narrowly missed being shot by Dave Graham, a drunken, irate cowboy gunning for Albert G. Boyce, the general manager, who had recently had a hand in getting him and his brother Tom fired from a neighboring ranch. This led to Mabry's participation in the subsequent gunfight, which resulted in the shooting of Dave and the arrest of Tom Graham by Oldham county sheriff James H. East. Mabry spent his last years in Selma, Alabama. He was a member of the Panhandle-Plains Historical Society and in 1927 wrote an account of his experiences with the XIT and Oldham County surveys. Two years later he published his memoirs of the 1873 surveys in the Panhandle-Plains Historical Review. He died at his home in Selma in June 1941.