Sixty Seven is an earth dam located in Sublette County, Wyoming, built in 1942. It carries a High hazard potential classification and has a fair condition assessment.
Dam profile
NID height · 32 ft32 ft tall and 956 ft long, taller than 74% 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 Sixty Seven
The primary purpose of Sixty Seven is irrigation. The dam stores and diverts water for agricultural irrigation, supporting farming operations in the surrounding area. The dam is owned by Rebecca Downs (private). It impounds the Spring Creek Offstream near Big Piney.
The dam stands 32 feet tall and stretches 956 feet across, creates a reservoir covering 371 acres, has a maximum storage capacity of 7,090 acre-feet, and collects water from a drainage area of 1 square miles. Completed in 1942, 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. Its condition is rated fair — the dam has minor deficiencies that are being addressed or do not pose an immediate safety threat. Notably, no emergency action plan is currently on file for this high-hazard dam. The most recent inspection on record was 06/06/2025.
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 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 | Sublette |
| Nearest City | Big Piney |
| River/Stream | Spring Creek Offstream |
| Coordinates | 42.59100, -110.20740 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 32 ft |
| Dam Height | 32 ft |
| Dam Length | 956 ft |
| Year Completed | 1942 (84 years old) |
Storage & Hydraulics
| NID Storage | 7,090 acre-ft |
| Max Storage | 7,090 acre-ft |
| Normal Storage | 6,087 acre-ft |
| Surface Area | 371 acres |
| Drainage Area | 1 sq mi |
| Max Discharge | 400 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Irrigation |
| Owner | Rebecca Downs |
| Owner Type | Private |
| Hazard Classification | High |
| Condition Assessment | Fair |
| Last Inspection | 06/06/2025 |
| Emergency Action Plan | No |
Identifiers
| NID ID | WY01275 |
| Federal ID | WY01275 |
| More Info | State Dam Safety Program |