Davis County is a county in northern Utah, United States. As of the 2020 United States Census, the population was 362,679, making it Utah's third-most populous county. Its county seat is Farmington, and its largest city by both population and area is Layton. Davis County is part of the Ogden-Clearfield, UT Metropolitan Statistical Area as well as the Salt Lake City-Provo-Orem, UT Combined Statistical Area.