Sixty Seven

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.

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.

At 32 feet, this dam is taller than 76% 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 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.

High HazardFair ConditionEmergency Action Plan: No

Location

StateWyoming
CountySublette
Nearest CityBig Piney
River/StreamSpring Creek Offstream
Coordinates42.59100, -110.20740

Physical Characteristics

Dam TypeEarth
NID Height32 ft
Dam Height32 ft
Dam Length956 ft
Year Completed1942 (84 years old)

Storage & Hydraulics

NID Storage7,090 acre-ft
Max Storage7,090 acre-ft
Normal Storage6,087 acre-ft
Surface Area371 acres
Drainage Area1 sq mi
Max Discharge400 cfs
Spillway TypeUncontrolled

Ownership & Safety

PurposeIrrigation
OwnerREBECCA DOWNS
Owner TypePrivate
Hazard ClassificationHigh
Condition AssessmentFair
Last Inspection06/06/2025
Emergency Action PlanNo

Identifiers

NID IDWY01275
Federal IDWY01275
More InfoState Dam Safety Program

Nearby Dams