Main Lake Dam is an earth dam located in Hamilton County, Illinois, built in 1976. It carries a Low hazard potential classification.
Dam profile
NID height · 28 ft28 ft tall and 2,200 ft long, taller than 62% 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 Main Lake Dam
The primary purpose of Main Lake Dam is water supply. The dam stores water for municipal, industrial, or agricultural use, helping ensure a reliable supply for the surrounding area. The dam is owned by Inland Steel Company (private). It impounds the Trib Wheeler Creek near Equality.
The dam stands 28 feet tall and stretches 2,200 feet across, and has a maximum storage capacity of 1,285 acre-feet. Completed in 1976, the structure is 50 years old.
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 07/29/2025.
Search for dams near your address to see all dams in your area with hazard classifications and safety data.
Location
| State | Illinois |
| County | Hamilton |
| Nearest City | Equality |
| River/Stream | Trib Wheeler Creek |
| Coordinates | 38.07334, -88.47481 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 28 ft |
| Dam Height | 28 ft |
| Dam Length | 2,200 ft |
| Year Completed | 1976 (50 years old) |
Storage & Hydraulics
| NID Storage | 1,285 acre-ft |
| Max Storage | 1,285 acre-ft |
| Normal Storage | 694 acre-ft |
| Spillway Type | Controlled |
Ownership & Safety
| Purpose | Water Supply |
| Owner | Inland Steel Company |
| Owner Type | Private |
| Hazard Classification | Low |
| Condition Assessment | Not assessed |
| Last Inspection | 07/29/2025 |
| Emergency Action Plan | No |
Identifiers
| NID ID | IL00935 |
| Federal ID | IL00935 |
| More Info | State Dam Safety Program |