Mauvaise Terre Lake Dam
High HazardNot Available ConditionEmergency Action Plan: Yes
Location
| State | Illinois |
| County | Morgan |
| Nearest City | JACKSONVILLE |
| River/Stream | MAUVAISE TERRE CREEK |
| Coordinates | 39.71881, -90.21702 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 30 ft |
| Dam Height | 30 ft |
| Dam Length | 850 ft |
| Year Completed | 1923 (103 years old) |
Storage & Hydraulics
| NID Storage | 5,624 acre-ft |
| Max Storage | 5,624 acre-ft |
| Normal Storage | 628 acre-ft |
| Surface Area | 262 acres |
| Drainage Area | 34 sq mi |
| Max Discharge | 25,539 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | CITY OF JACKSONVILLE |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Not Available |
| Last Inspection | 08/15/2025 |
| Emergency Action Plan | Yes |