Upper Stillwater is a federal-owned concrete gravity dam located in Duchesne, Utah, along the Rock Creek river. Completed in 1986 by the Bureau of Reclamation, this structure serves primarily for irrigation purposes, but also supports recreation and water supply needs in the area. With a maximum storage capacity of 35,253 acre-feet and a normal storage of 33,123 acre-feet, Upper Stillwater plays a crucial role in managing water resources in the region.

Standing at a height of 285 feet and a length of 2,660 feet, Upper Stillwater dam has a spillway width of 600 feet for uncontrolled discharge during high water events. Despite its high hazard potential, the condition assessment of the dam is currently not available, and its last inspection was conducted in August 2020. While the risk assessment is moderate, the emergency action plan for the dam was last revised in June 2020, indicating a commitment to preparedness and safety measures in case of emergencies. For water resource and climate enthusiasts, Upper Stillwater represents a key infrastructure contributing to the sustainability and resilience of water management in the region.