Illinois Power Company Lake Dam is an earth dam located in Vermilion County, Illinois, built in 1954. It carries a Low hazard potential classification.
Dam profile
NID height · 80 ft80 ft tall and 500 ft long, taller than 97% of U.S. dams with a recorded height. Height is drawn to scale against a ten-story building, about 100 ft; the profile is a generic embankment section and the water level is illustrative.
About Illinois Power Company Lake Dam
The primary purpose of Illinois Power Company Lake Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Dynegy (public utility). It impounds the Vermillion River near Hillery.
The dam stands 80 feet tall and stretches 500 feet across, and has a maximum storage capacity of 2,400 acre-feet. Completed in 1954, 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 09/08/2025.
At 80 feet, this dam is taller than 97% of all dams in the United States.
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Location
| State | Illinois |
| County | Vermilion |
| Nearest City | Hillery |
| River/Stream | Vermillion River |
| Coordinates | 40.17225, -87.74571 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 80 ft |
| Dam Height | 80 ft |
| Dam Length | 500 ft |
| Year Completed | 1954 (72 years old) |
Storage & Hydraulics
| NID Storage | 2,400 acre-ft |
| Max Storage | 2,400 acre-ft |
| Normal Storage | 2,300 acre-ft |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | Dynegy |
| Owner Type | Public Utility |
| Hazard Classification | Low |
| Condition Assessment | Not assessed |
| Last Inspection | 09/08/2025 |
| Emergency Action Plan | No |
Identifiers
| NID ID | IL00522 |
| Federal ID | IL00522 |
| More Info | State Dam Safety Program |