Andover
- County:
- Henry County
- County Seat:
- No
- Area (mi²):
- 0.99
- State:
- Illinois
Andover is a village located in Henry County, Illinois. Andover has a 2026 population of 539. Andover is currently declining at a rate of -0.37% annually and its population has decreased by -2.88% since the most recent census, which recorded a population of 555 in 2020.