Beartrack Treatment Lagoon, also known as Beartrack Mine Cell A Lagoon, is a private water treatment facility located in Lemhi County, Idaho. This lagoon plays a crucial role in the treatment of tailings from mining operations, with a primary purpose of managing and containing these materials. Built in 1995, the lagoon has a dam height of 20 feet and a storage capacity of 76.7 acre-feet, serving an important function in environmental protection and water resource management.

Situated near Napias Creek and Panther Creek, the Beartrack Treatment Lagoon covers an area of 2.5 acres and has a drainage area of 0.2 square miles. Despite being classified as having a low hazard potential, the facility is subject to state regulation and inspection, ensuring that it meets safety standards and environmental requirements. The lagoon's spillway is uncontrolled, with a width of 10 feet, and its condition was last assessed as satisfactory in August 2017.

Overall, the Beartrack Treatment Lagoon serves as a vital component in the management of water resources in the region, particularly in relation to mining activities. With its strategic location and efficient design, the lagoon effectively contains tailings and protects surrounding waterways from potential contamination. As a well-maintained and regulated facility, it contributes to the sustainable management of water resources in Lemhi County, Idaho, showcasing the importance of responsible water treatment practices in the face of climate and environmental challenges.