Posen
- County:
- Cook County
- County Seat:
- No
- Area (mi²):
- 1.169
- State:
- Illinois
Posen is a village located in Cook County, Illinois. Posen has a 2026 population of 5,413. Posen is currently growing at a rate of 0.65% annually but its population has decreased by -2.85% since the most recent census, which recorded a population of 5,572 in 2020.