St. George or Saint George is a city in and the county seat of Washington County, Utah, United States. Located in southwestern Utah on the Arizona border, it is the principal city of the St. George Metropolitan Statistical Area. The city lies in the northeasternmost part of the Mojave Desert, immediately south of the Pine Valley Mountains, which mark the southern boundary of the Great Basin. St. George lies slightly northwest of the Colorado Plateau, which ends at the Hurricane Fault.