 Its county seat is Farmington, and its largest city 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.The legislature of the provisional State of Deseret defined the county in an October 5, 1850 act, which also designated Farmington as the seat due to its location midway between boundaries at the Weber River on the north and the Jordan River on the south.