Hall Mill Dam, also known as Lake Fulmor Dam, is a federal-owned structure located in Riverside, California. Completed in 1949, this earth dam stands at a height of 40 feet and stretches 220 feet in length. It serves a primary purpose other than water storage and is classified as having a high hazard potential. Despite its age, the condition of the dam is currently not rated, and it undergoes inspections annually to ensure its safety.

Managed by the Forest Service, Hall Mill Dam does not fall under state regulation or jurisdiction. It features an uncontrolled spillway and is constructed with a stone core and built on rock and soil foundations. The dam's risk assessment indicates a moderate level of risk, with no emergency action plan in place as of the last data update in May 2021. With its captivating history and design, Hall Mill Dam stands as a notable landmark for water resource and climate enthusiasts interested in exploring the intersection of infrastructure and environmental conservation in California's diverse landscape.