Vernal, the county seat and largest city in Uintah County, is in northeastern Utah, approximately 175 miles east of Salt Lake City and 20 miles we…Vernal, the county seat and largest city in Uintah County, is in northeastern Utah, approximately 175 miles east of Salt Lake City and 20 miles west of the Colorado border. As of the 2020 census, the city population was 10,079. The population has since grown to 10,432 as of the 2022 population estimate.