Timber Lake Dam is an earth dam located in Carroll County, Illinois, built in 1960. It carries a Significant hazard potential classification.
Dam profile
NID height · 25 ft25 ft tall and 466 ft long, taller than 50% of U.S. dams with a recorded height. Height is drawn to scale against a two-story house, about 25 ft; the profile is a generic embankment section and the water level is illustrative.
About Timber Lake Dam
The primary purpose of Timber Lake Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Timber Lake Campground (private). It impounds the Trib East Johnson Creek near Daggett.
The dam stands 25 feet tall and stretches 466 feet across, and has a maximum storage capacity of 155 acre-feet. Completed in 1960, the structure is well into its service life at over 50 years old.
This dam has a significant hazard potential classification, meaning that a failure could cause significant economic damage — flooding roads, bridges, or property downstream — but is not expected to result in loss of life. The most recent inspection on record was 10/22/2025.
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Location
| State | Illinois |
| County | Carroll |
| Nearest City | Daggett |
| River/Stream | Trib East Johnson Creek |
| Coordinates | 42.05189, -89.94142 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 25 ft |
| Dam Height | 25 ft |
| Dam Length | 466 ft |
| Year Completed | 1960 (66 years old) |
Storage & Hydraulics
| NID Storage | 155 acre-ft |
| Max Storage | 155 acre-ft |
| Normal Storage | 87 acre-ft |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | Timber Lake Campground |
| Owner Type | Private |
| Hazard Classification | Significant |
| Condition Assessment | Not assessed |
| Last Inspection | 10/22/2025 |
| Emergency Action Plan | No |
Identifiers
| NID ID | IL00841 |
| Federal ID | IL00841 |
| More Info | State Dam Safety Program |