Algonquin Dam
Significant HazardNot Available ConditionEmergency Action Plan: Yes
Location
| State | Illinois |
| County | McHenry |
| Nearest City | ALGONQUIN |
| River/Stream | FOX RIVER |
| Coordinates | 42.16574, -88.29009 |
Physical Characteristics
| Dam Type | Concrete |
| NID Height | 9 ft |
| Dam Height | 9 ft |
| Dam Length | 300 ft |
| Year Completed | 1947 (79 years old) |
Storage & Hydraulics
| NID Storage | 24,200 acre-ft |
| Max Storage | 24,200 acre-ft |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | ILLINOIS DEPARTMENT OF NATURAL RESOURCES |
| Owner Type | State |
| Hazard Classification | Significant |
| Condition Assessment | Not Available |
| Last Inspection | 10/28/2025 |
| Emergency Action Plan | Yes |