Dunlap Lake Dam is an earth dam located in Madison County, Illinois, built in 1941. It carries a High hazard potential classification.
Dam profile
NID height · 45 ft45 ft tall and 840 ft long, taller than 90% 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 Dunlap Lake Dam
The primary purpose of Dunlap Lake Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Dunlap Lake Property Owners Association (private). It impounds the Mooney Creek near Edwardsville.
The dam stands 45 feet tall and stretches 840 feet across, creates a reservoir covering 205 acres, has a maximum storage capacity of 5,660 acre-feet, and collects water from a drainage area of 4 square miles. Completed in 1941, 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 09/12/2025.
At 45 feet, this dam is taller than 90% 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 | Madison |
| Nearest City | Edwardsville |
| River/Stream | Mooney Creek |
| Coordinates | 38.80774, -89.93863 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 45 ft |
| Dam Height | 45 ft |
| Dam Length | 840 ft |
| Year Completed | 1941 (85 years old) |
Storage & Hydraulics
| NID Storage | 5,660 acre-ft |
| Max Storage | 5,660 acre-ft |
| Normal Storage | 3,010 acre-ft |
| Surface Area | 205 acres |
| Drainage Area | 4 sq mi |
| Max Discharge | 13,443 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | Dunlap Lake Property Owners Association |
| Owner Type | Private |
| Hazard Classification | High |
| Condition Assessment | Not assessed |
| Last Inspection | 09/12/2025 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | IL00186 |
| Federal ID | IL00186 |
| More Info | State Dam Safety Program |