Cedar Lake Dam
Cedar Lake Dam is an earth dam located in Jackson County, Illinois, built in 1974. It carries a High hazard potential classification.
About Cedar Lake Dam
The primary purpose of Cedar Lake 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 Carbondale (local government). It impounds the Cedar Creek near Rattlesnake Ferry.
The dam stands 74 feet tall and stretches 1,690 feet across, creates a reservoir covering 1,750 acres, has a maximum storage capacity of 49,336 acre-feet, and collects water from a drainage area of 30 square miles. Completed in 1974, 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 10/24/2025.
At 74 feet, this dam is taller than 97% of all dams in the United States.
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 | Jackson |
| Nearest City | Rattlesnake Ferry |
| River/Stream | Cedar Creek |
| Coordinates | 37.66292, -89.28585 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 74 ft |
| Dam Height | 74 ft |
| Dam Length | 1,690 ft |
| Year Completed | 1974 (52 years old) |
Storage & Hydraulics
| NID Storage | 49,336 acre-ft |
| Max Storage | 49,336 acre-ft |
| Normal Storage | 28,365 acre-ft |
| Surface Area | 1,750 acres |
| Drainage Area | 30 sq mi |
| Max Discharge | 10,234 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | CITY OF CARBONDALE |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Not Available |
| Last Inspection | 10/24/2025 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | IL00033 |
| Federal ID | IL00033 |
| More Info | State Dam Safety Program |