Whiteside County, Illinois

Whiteside County
Location within the U.S. state of Illinois
Illinois's location within the U.S.
Coordinates: 41°45′N 89°55′W / 41.75°N 89.91°W / 41.75; -89.91
Country United States
State Illinois
Founded1836
Named afterSamuel Whiteside
SeatMorrison
Largest citySterling
Area
  Total
697 sq mi (1,810 km2)
  Land684 sq mi (1,770 km2)
  Water12 sq mi (30 km2)  1.8%
Population
 (2020)
  Total
55,691
  Estimate 
(2023)
54,498
  Density80/sq mi (31/km2)
Time zoneUTC−6 (Central)
  Summer (DST)UTC−5 (CDT)
Congressional district17th
Websitewww.whitesidecountyil.gov

Whiteside County is a county located in the U.S. state of Illinois. According to the 2020 census, it had a population of 55,691. Its county seat is Morrison. The county is bounded on the west by the Mississippi River. Whiteside County comprises the Sterling, IL Micropolitan Statistical Area, which is also included in the Dixon-Sterling, IL Combined Statistical Area. U.S. President Ronald Reagan was born in 1911 in the Whiteside County community of Tampico.