Thunderbird Lake 1 Dam
Illinois — McHenry County — SLEEPY HOLLOW CREEK
Location
| State | Illinois |
| County | McHenry |
| River | SLEEPY HOLLOW CREEK |
| Coordinates | 42.27641, -88.26982 |
Physical Characteristics
| NID Height | 7 ft |
| Dam Height | 7 ft |
| Dam Length | 420 ft |
| NID Storage | 395 acre-ft |
| Max Storage | 395 acre-ft |
| Surface Area | — |
Safety Classification
| Hazard Potential | Low |
| Condition Assessment | Not Available |
| EAP Status | No |
| Last Inspection | October 3, 2025 |
| Inspection Frequency | 5 |
Dam Information
| Year Completed | 1965 |
| Primary Purpose | Recreation |
| Dam Type | Earth |
| Owner Type | Private |
| Owner | CHARLES F. WIRTH |
| Other Name | Thunderbird Lake |
Location Map
About This Dam Record
Dam safety data is maintained by the Army Corps of Engineers National Inventory of Dams (NID). High-hazard dams are those where failure could cause loss of life or major property damage downstream.