Washington County is a county in the southwestern corner of Utah, United States. As of the 2020 United States Census, the population was 180,279, making it the fifth-most populous county in Utah. Its county seat and largest city is St. George. The county was created in 1852 and organized in 1856. It was named after the first President of the United States, George Washington. A portion of the Paiute Indian Reservation is in western Washington County. Washington County comprises the St. George, UT Metropolitan Statistical Area.