Treasure Lake Dam is an earth dam located in Adams County, Illinois, built in 1989. It carries a High hazard potential classification.
Dam profile
NID height · 15 ft15 ft tall and 320 ft long. 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 Treasure Lake Dam
The primary purpose of Treasure Lake Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Robert Lansing (private). It impounds the Trib Cedar Creek near Quincy.
The dam stands 15 feet tall and stretches 320 feet across, creates a reservoir covering 4 acres, has a maximum storage capacity of 50 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1989, the structure is 37 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 08/12/2025.
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 | Adams |
| Nearest City | Quincy |
| River/Stream | Trib Cedar Creek |
| Coordinates | 39.96713, -91.38061 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 15 ft |
| Dam Height | 15 ft |
| Dam Length | 320 ft |
| Year Completed | 1989 (37 years old) |
Storage & Hydraulics
| NID Storage | 50 acre-ft |
| Max Storage | 50 acre-ft |
| Surface Area | 4 acres |
| Drainage Area | 0 sq mi |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | Robert Lansing |
| Owner Type | Private |
| Hazard Classification | High |
| Condition Assessment | Not assessed |
| Last Inspection | 08/12/2025 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | IL50550 |
| Federal ID | IL50550 |
| More Info | State Dam Safety Program |