The Wachusett Dam in Clinton, Massachusetts impounds the Nashua River creating the Wachusett Reservoir. Construction started in 1897 and was completed in 1905. It is part of the Nashua River Watershed.
This dam is part of greater Boston's water system, maintained and controlled by the Massachusetts Water Resources Authority. Its discharge is into the Nashua River. When it was completed in 1905, the Wachusett Reservoir was the largest public water supply reservoir in the world. At that time, the Wachusett Reservoir Dam was the largest gravity dam in the world as well.
Wikipedia https://en.wikipedia.org/wiki/Wachusett_Dam
Address 01510, United States
Coordinates 42°24'13.79" N -71°41'18.113" E
