Keyhole Dam
Keyhole Dam is an earth dam located in Crook County, Wyoming, built in 1952. It carries a High hazard potential classification.
About Keyhole Dam
The primary purpose of Keyhole Dam is flood risk reduction. The dam is designed to control downstream flooding by temporarily storing excess water during storms and releasing it at a controlled rate. The dam is owned by Bureau Of Reclamation (federal). It impounds the Belle Fourche River near Hulett.
The dam stands 168 feet tall and stretches 3,420 feet across, creates a reservoir covering 9,411 acres, has a maximum storage capacity of 629,025 acre-feet, and collects water from a drainage area of 1,949 square miles. Completed in 1952, 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 08/27/2020.
At 168 feet, this dam is taller than 99% 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 Wyoming 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 | Wyoming |
| County | Crook |
| Nearest City | Hulett |
| River/Stream | Belle Fourche River |
| Coordinates | 44.38250, -104.77840 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 168 ft |
| Dam Height | 168 ft |
| Dam Length | 3,420 ft |
| Year Completed | 1952 (74 years old) |
Storage & Hydraulics
| NID Storage | 629,025 acre-ft |
| Max Storage | 629,025 acre-ft |
| Normal Storage | 334,215 acre-ft |
| Surface Area | 9,411 acres |
| Drainage Area | 1,949 sq mi |
| Max Discharge | 10,850 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | BUREAU OF RECLAMATION |
| Owner Type | Federal |
| Hazard Classification | High |
| Condition Assessment | Not Available |
| Last Inspection | 08/27/2020 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | WY01380 |
| Federal ID | WY01380 |
| More Info | State Dam Safety Program |