Cilca Lake Dam is an earth dam located in Sangamon County, Illinois, built in 1968. It carries a Low hazard potential classification.
Dam profile
NID height · 43 ft43 ft tall and 505 ft long, taller than 89% 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 Cilca Lake Dam
The primary purpose of Cilca Lake Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Camp Cilca (private). It impounds the Trib Sangamon River near Petersburg.
The dam stands 43 feet tall and stretches 505 feet across, and has a maximum storage capacity of 164 acre-feet. Completed in 1968, the structure is well into its service life at over 50 years old.
This dam has a low hazard potential classification, meaning that failure would cause minimal damage, limited primarily to the dam owner's property, with no expected loss of life. The most recent inspection on record was 08/05/2025.
At 43 feet, this dam is taller than 89% of dams nationwide.
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Location
| State | Illinois |
| County | Sangamon |
| Nearest City | Petersburg |
| River/Stream | Trib Sangamon River |
| Coordinates | 39.89493, -89.73513 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 43 ft |
| Dam Height | 43 ft |
| Dam Length | 505 ft |
| Year Completed | 1968 (58 years old) |
Storage & Hydraulics
| NID Storage | 164 acre-ft |
| Max Storage | 164 acre-ft |
| Normal Storage | 126 acre-ft |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | Camp Cilca |
| Owner Type | Private |
| Hazard Classification | Low |
| Condition Assessment | Not assessed |
| Last Inspection | 08/05/2025 |
| Emergency Action Plan | No |
Identifiers
| NID ID | IL00806 |
| Federal ID | IL00806 |
| More Info | State Dam Safety Program |