An 1876 International & Great Northern Railroad siding called "Stiles Switch" for landowners J.E. and F.N. Stiles, grew into a shipping point for the Swiss and Germans who settled in this area. The post office that opened in 1901 was named for Methodist minister and historian Homer S. Thrall. Nearby oil discoveries and sudden growth caused the town to be incorporated in 1915. The 38.21-inch rainfall of Sept. 8-9, 1921, gave Thrall a world record. Since 1961, Texas A.&.M. University agricultural research center has operated here. Farming remains the basic local industry. (1976)