Gaines County went from open range to oil country in about 50 years

The Texas legislature created Gaines County in 1876 from Bexar County. It was named for James Gaines, a merchant who signed the Texas Declaration of Independence. The area had been Comanche territory until U.S. Army campaigns in 1875-1876. The first permanent settler, C. C. Meddin, arrived in 1880. By 1900, only 55 people lived in the county.

The county organized formally in 1905, and Seminole became the county seat after a group of New York investors donated land for the town. Early growth came from ranching, then cotton farming in the 1920s. Oil production began in 1935, which helped the county survive the Great Depression, and the Seminole Pool was discovered in 1936. A Mennonite community also settled near Seminole and remains part of the county's character today.