Upper Sunshine

About Upper Sunshine

The primary purpose of Upper Sunshine is irrigation. The dam stores and diverts water for agricultural irrigation, supporting farming operations in the surrounding area. The dam is owned by Greybull Valley Irrigation District (private). It impounds the Greybull River (offstream) near Meeteetse.

The dam stands 160 feet tall and stretches 1,150 feet across, creates a reservoir covering 1,156 acres, has a maximum storage capacity of 65,100 acre-feet, and collects water from a drainage area of 12 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. An emergency action plan is in place for this dam. The most recent inspection on record was 09/30/2025.

At 160 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.

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