Waukegan
- County:
- Lake County
- County Seat:
- Yes
- Area (mi²):
- 24.217
- State:
- Illinois
Waukegan is a city located in Lake County, Illinois. Waukegan has a 2026 population of 88,570. It is also the county seat of Lake County. Waukegan is currently growing at a rate of 0.28% annually but its population has decreased by -0.62% since the most recent census, which recorded a population of 89,122 in 2020.