Algonquin
- County:
- McHenry County
- County Seat:
- No
- Area (mi²):
- 12.539
- State:
- Illinois
Algonquin is a village located in McHenry County, Illinois. Algonquin has a 2026 population of 30,539. Algonquin is currently growing at a rate of 1.08% annually and its population has increased by 2.9% since the most recent census, which recorded a population of 29,679 in 2020.