Lake Jaycee Dam
Lake Jaycee Dam is an earth dam located in Jefferson County, Illinois, built in 1905. It carries a Significant hazard potential classification.
About Lake Jaycee Dam
The primary purpose of Lake Jaycee Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by City Of Mount Vernon (local government). It impounds the Trib Casey Fork near Mount Vernon.
The dam stands 30 feet tall and stretches 875 feet across, creates a reservoir covering 115 acres, has a maximum storage capacity of 2,110 acre-feet, and collects water from a drainage area of 2 square miles. Completed in 1905, the structure is over a century 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. An emergency action plan is in place for this dam. The most recent inspection on record was 06/22/2025.
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Location
| State | Illinois |
| County | Jefferson |
| Nearest City | Mount Vernon |
| River/Stream | Trib Casey Fork |
| Coordinates | 38.36974, -88.89895 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 30 ft |
| Dam Height | 30 ft |
| Dam Length | 875 ft |
| Year Completed | 1905 (121 years old) |
Storage & Hydraulics
| NID Storage | 2,110 acre-ft |
| Max Storage | 2,110 acre-ft |
| Normal Storage | 1,024 acre-ft |
| Surface Area | 115 acres |
| Drainage Area | 2 sq mi |
| Max Discharge | 3,257 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | CITY OF MOUNT VERNON |
| Owner Type | Local Government |
| Hazard Classification | Significant |
| Condition Assessment | Not Available |
| Last Inspection | 06/22/2025 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | IL00170 |
| Federal ID | IL00170 |
| More Info | State Dam Safety Program |