Jefferson County, Wisconsin

Jefferson County
Jefferson County courthouse
Location within the U.S. state of Wisconsin
Wisconsin's location within the U.S.
Coordinates: 43°01′N 88°47′W / 43.02°N 88.78°W / 43.02; -88.78
Country United States
State Wisconsin
Founded1839
Named afterThomas Jefferson
SeatJefferson
Largest cityWatertown
Area
  Total
583 sq mi (1,510 km2)
  Land556 sq mi (1,440 km2)
  Water26 sq mi (70 km2)  4.5%
Population
 (2020)
  Total
84,900
  Estimate 
(2023)
85,743
  Density150/sq mi (56/km2)
Time zoneUTC−6 (Central)
  Summer (DST)UTC−5 (CDT)
Congressional district5th
Websitewww.jeffersoncountywi.gov

Jefferson County is a county in the U.S. state of Wisconsin. As of the 2020 census, the population was 84,900. Its county seat is Jefferson. Jefferson County comprises the Watertown-Fort Atkinson, WI Micropolitan Statistical Area, which is also included in the Milwaukee-Racine-Waukesha, WI Combined Statistical Area.