Located in Itasca County, Minnesota, Hill Annex No. 3 is a privately owned earth dam constructed in 1954 for tailings management. This dam, standing at a height of 63 feet and spanning 10,700 feet in length, serves the primary purpose of tailings storage with a storage capacity of 3,346 acre-feet. The dam is regulated by the Minnesota Department of Natural Resources (MNDNR EWR) and is subject to state permitting, inspection, and enforcement.

The dam poses a significant hazard potential and has not been rated for its condition assessment as of the last inspection in July 2012. It falls under the jurisdiction of local residents and the St. Paul District of the US Army Corps of Engineers. The dam's primary source agency is the state of Minnesota, and it is situated along the Swan River-Tr. With a drainage area of 0.4 square miles, the dam plays a crucial role in managing water resources in the region and highlights the importance of proper dam maintenance and regulation for climate and water resource enthusiasts.

Despite being a privately owned structure, Hill Annex No. 3's presence underscores the interconnectedness of water resources management, climate resilience, and regulatory oversight. As a key component in the local watershed system, the dam's condition and functionality are essential for ensuring the safety and sustainability of water resources in the area. With its significant hazard potential and state-regulated status, this dam serves as a focal point for ongoing monitoring, inspection, and enforcement efforts to safeguard both the environment and local communities from potential risks associated with dam failure or mismanagement.