Forest Lake Dam
Forest Lake Dam is an earth dam located in Lake County, Illinois, built in 1935. It carries a High hazard potential classification.
About Forest Lake Dam
The primary purpose of Forest Lake Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Ela Township Highway Department (local government). It impounds the Trib Indian Creek near Hawthorne Woods.
The dam stands 11 feet tall and stretches 125 feet across, creates a reservoir covering 38 acres, has a maximum storage capacity of 561 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1935, 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 02/18/2026.
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 | Lake |
| Nearest City | Hawthorne Woods |
| River/Stream | Trib Indian Creek |
| Coordinates | 42.21483, -88.05051 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 11 ft |
| Dam Height | 11 ft |
| Dam Length | 125 ft |
| Year Completed | 1935 (91 years old) |
Storage & Hydraulics
| NID Storage | 561 acre-ft |
| Max Storage | 561 acre-ft |
| Normal Storage | 457 acre-ft |
| Surface Area | 38 acres |
| Drainage Area | 0 sq mi |
| Max Discharge | 1,684 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | ELA TOWNSHIP HIGHWAY DEPARTMENT |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Not Available |
| Last Inspection | 02/18/2026 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | IL00638 |
| Federal ID | IL00638 |
| More Info | State Dam Safety Program |