Gunlock is an unincorporated community in western Washington County, Utah, United States, north of Gunlock State Park. It lies along local roads northwest of the city of St. George, the county seat of Washington County. Its elevation is 3,658 feet (1,115 m). Although Gunlock is unincorporated, it has a post office, with the ZIP code of 84733.
A plaque posted in the town of Gunlock describes the origin of the name of the town.
William Haynes (Gunlock) Hamblin, Born Oct. 28, 1830 Salem Ohio. Married Mary A., and Betsy Leavitt. Died May 8, 1872 at Clover Valley, Nevada from efforts of poison given to him before he could testify concerning a Silver mine he had discovered and was selling. But Truth crushed to Earth shall rise again, so we anxiously await for that day when men shall stand before the bar of justice and account for every word and deed. He was the father of 17 children, and was given the nickname “Gunlock” by George A. Smith, Apostle for whom he drove wagon across the plains….