Lake Matherville Dam is an earth dam located in Mercer County, Illinois, built in 1926. It carries a Low hazard potential classification.
Dam profile
NID height · 37 ft37 ft tall and 606 ft long, taller than 83% 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 Lake Matherville Dam
The primary purpose of Lake Matherville 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 Matherville (local government). It impounds the Trib Edwards River near Matherville.
The dam stands 37 feet tall and stretches 606 feet across, and has a maximum storage capacity of 158 acre-feet. Completed in 1926, the structure is well-established, with more than 75 years of service.
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 05/02/2025.
At 37 feet, this dam is taller than 83% of dams nationwide.
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Location
| State | Illinois |
| County | Mercer |
| Nearest City | Matherville |
| River/Stream | Trib Edwards River |
| Coordinates | 41.26153, -90.61159 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 37 ft |
| Dam Height | 37 ft |
| Dam Length | 606 ft |
| Year Completed | 1926 (100 years old) |
Storage & Hydraulics
| NID Storage | 158 acre-ft |
| Max Storage | 158 acre-ft |
| Normal Storage | 81 acre-ft |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | City of Matherville |
| Owner Type | Local Government |
| Hazard Classification | Low |
| Condition Assessment | Not assessed |
| Last Inspection | 05/02/2025 |
| Emergency Action Plan | No |
Identifiers
| NID ID | IL00508 |
| Federal ID | IL00508 |
| More Info | State Dam Safety Program |