William H. Day, trail driver and livestock entrepreneur, son of Jesse and Sarah (Logan) Day, was born on May 8, 1833, in Cassville, Georgia. The family moved to Bastrop, Texas, in 1847. They later lived in San Antonio and then in Hays County. Day graduated from Cumberland University in 1858 with a degree in engineering. On his first cattle drive in 1860, his father drowned. Day and his brother James Monroe Day attempted to drive the herd to Kansas City but were turned back by angry landowners. They nevertheless delivered the herd to St. Louis. Day continued in the cattle business after a brief tenure in the military in what is now Coleman County, Texas. In 1862 he drove herds to Louisiana markets, and after the Civil War he was involved in the lumber business in East Texas. In 1868 or 1869 he drove a herd of cattle to Abilene, Kansas, in partnership with his brother-in-law, Jesse L. Driskill. In 1873 he was employed by the St. Louis livestock-commission firm of Hunter and Evans, and by 1875, after a brief return to the cattle business, he was the company's manager for Texas.
Day realized that the future of the cattle business depended on land ownership and fenced pastures, and he took steps to acquire thousands of acres from the school-land tracts of Brazoria and Fort Bend counties, which were situated at the confluence of the Concho and Colorado rivers south of Camp Colorado in Coleman County. In 1878 he bought a considerable plot in what was to become Coleman County and made several drives to Dodge City, Kansas. In the next year he married Mabel Doss (see LEA, MABEL D.) of Denison, and in the winter of 1880 their daughter Willie Mabel was born. Day died on June 14, 1881, from injuries sustained in a stampede and left his widow and infant child deeply in debt and burdened with a massive ranch operation. Mabel Doss Day turned misfortune into success, however, and during the 1880s became known as the "Cattle Queen of Texas" for her skillful management.