
Auburn
- County:
- Sangamon County
- County Seat:
- No
- Area (mi²):
- 4.124
- State:
- Illinois
Auburn is a city located in Sangamon County, Illinois. Auburn has a 2025 population of 4,376. Auburn is currently declining at a rate of -0.77% annually and its population has decreased by -3.72% since the most recent census, which recorded a population of 4,545 in 2020.
The average household income in Auburn is $97,026 with a poverty rate of 6.65%. The median age in Auburn is 36 years: 33.2 years for males, and 38.2 years for females.