Androscoggin river dams

The dams that confine and regulate the flow of water from the many lakes above the source of the Androscoggin River are (top to bottom) Upper Dam, between Mooselookmeguntic and Upper Richardson lakes; Middle Dam, between Lower Richardson lake and Rapid River; Errol Dam, on the Androscoggin a short distance below Umbagog Lake; and Aziscohos Dam, erected on the Magalloway River in 1909-1911, and for a time the world’s largest concrete dam.