Lake Summerset Dam is an earth dam located in Winnebago County, Illinois, built in 1969. It carries a High hazard potential classification.
Dam profile
NID height · 44 ft44 ft tall and 1,794 ft long, taller than 89% 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 Summerset Dam
The primary purpose of Lake Summerset Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Lake Summerset Association, Inc. (private). It impounds the South Branch Otter Creek near Durand.
The dam stands 44 feet tall and stretches 1,794 feet across, creates a reservoir covering 301 acres, has a maximum storage capacity of 7,312 acre-feet, and collects water from a drainage area of 6 square miles. Completed in 1969, the structure is well into its service life at over 50 years old.
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 10/13/2025.
At 44 feet, this dam is taller than 89% 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 | Winnebago |
| Nearest City | Durand |
| River/Stream | South Branch Otter Creek |
| Coordinates | 42.44806, -89.38435 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 44 ft |
| Dam Height | 44 ft |
| Dam Length | 1,794 ft |
| Year Completed | 1969 (57 years old) |
Storage & Hydraulics
| NID Storage | 7,312 acre-ft |
| Max Storage | 7,312 acre-ft |
| Normal Storage | 4,985 acre-ft |
| Surface Area | 301 acres |
| Drainage Area | 6 sq mi |
| Max Discharge | 1,230 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | Lake Summerset Association, Inc. |
| Owner Type | Private |
| Hazard Classification | High |
| Condition Assessment | Not assessed |
| Last Inspection | 10/13/2025 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | IL00572 |
| Federal ID | IL00572 |
| More Info | State Dam Safety Program |