Pierce Mills is a historic hydroelectric dam located on the Passumpsic River in St. Johnsbury, Vermont. Built in 1928, this concrete gravity dam stands at a height of 19 feet and has a length of 140 feet. With a storage capacity of 300 acre-feet, it serves as a key source of hydroelectric power in the area. The dam is owned by a public utility and is not state-regulated, making it an important asset for the local community.

The dam has a low hazard potential and is currently rated as "Not Rated" in terms of its condition assessment. Despite not being regularly inspected or permitted by state agencies, Pierce Mills continues to operate efficiently, providing clean and renewable energy to the region. The last inspection of the dam was conducted in May 2000, and it meets all necessary safety guidelines. The surrounding area is at low risk for inundation, and emergency preparedness plans are in place to ensure the safety of nearby residents in the event of a dam failure.

With its picturesque location on the Passumpsic River and its important role in supplying hydroelectric power, Pierce Mills remains a significant landmark in Caledonia County, Vermont. As a multi-arch dam with a solid foundation on rock and soil, it represents a sustainable and reliable source of renewable energy. Climate and water resource enthusiasts will appreciate the historical significance and environmental impact of this well-maintained dam.