William L. Mabry, also known as Mabrey, educator, county official, lawman, miller, and state representative, was born in Rockingham County, North Carolina, on October 13, 1815, the son of Cornelius and Mary (Jewell) Mabrey. The Mabrey family emigrated from North Carolina to Indiana in 1823. Mabrey himself set out on his own in 1837, establishing himself as a schoolteacher in Muncie, Indiana. Later he relocated to Wayne County, Missouri, where he worked as a schoolteacher and served as county clerk. In 1848 Mabrey immigrated to Texas, settling in western Bowie County. Around this time he began representing himself as Mabry. In 1854 Mabry relocated to a homestead four miles west of Clarksville, Red River County. This grew into the community of Mabry where he operated a cotton gin and grist mill and served as a deputy U.S. marshal and justice of the peace. Mabry continued his involvement in community affairs throughout the 1860s and 1870s, organizing and teaching at Clarksville's first school in 1870 and winning election as representative for District Nine—comprised of Red River and Titus counties—to the Thirteenth Texas Legislature in 1872.
Mabry married four times. His first marriage to Hannah Hill in 1842 produced one son and two daughters. Following Hannah's death around 1850, Mabry married Sarah Enloe in 1851. She died in 1852 however, and Mabry remarried the following year to Permelia Chaney. This couple had six sons and four daughters. Permelia died in 1881; Mabry married a final time to Margaret Bruce Hornaday in 1882. William Mabry died at his homestead on June 1, 1896, and was buried near Clarksville at Old Shamrock Cemetery. He was a Christian, a Mason, and a member of the Woodmen of the World.