Miller Lake Dam
Miller Lake Dam is an earth dam located in Jefferson County, Illinois, built in 1947. It carries a High hazard potential classification.
About Miller Lake Dam
The primary purpose of Miller Lake 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 40 feet tall and stretches 870 feet across, creates a reservoir covering 142 acres, has a maximum storage capacity of 3,510 acre-feet, and collects water from a drainage area of 4 square miles. Completed in 1947, the structure is well-established, with more than 75 years of service.
This dam carries a high hazard potential classification, which means that a failure or uncontrolled release of water would likely cause loss of human life. This classification reflects the consequences of failure, not the likelihood — it indicates that people live or work in the area downstream. An emergency action plan is in place for this dam. The most recent inspection on record was 06/02/2025.
At 40 feet, this dam is taller than 87% of dams nationwide.
Living Downstream
If you live or work downstream of this dam, consider taking these steps: learn your local evacuation routes, check whether your county emergency management office has a dam failure inundation map, and sign up for local emergency alerts. The Illinois dam safety program can provide more specific information about emergency planning for this structure.
Search for dams near your address to see all dams in your area with hazard classifications and safety data.
Location
| State | Illinois |
| County | Jefferson |
| Nearest City | Mount Vernon |
| River/Stream | Trib Casey Fork |
| Coordinates | 38.39671, -88.89326 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 40 ft |
| Dam Height | 40 ft |
| Dam Length | 870 ft |
| Year Completed | 1947 (79 years old) |
Storage & Hydraulics
| NID Storage | 3,510 acre-ft |
| Max Storage | 3,510 acre-ft |
| Normal Storage | 1,593 acre-ft |
| Surface Area | 142 acres |
| Drainage Area | 4 sq mi |
| Max Discharge | 6,550 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | CITY OF MOUNT VERNON |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Not Available |
| Last Inspection | 06/02/2025 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | IL00171 |
| Federal ID | IL00171 |
| More Info | State Dam Safety Program |