Kennebec River
Coburn Mtn. lies within the watershed of the Kennebec River. The northern end of the southeast side of Coburn drains into Mountain Brook, then into Cold Stream and the Kennebec River. The southern end drains into Salmon Stream, then into the Dead River, another tributary of the Kennebec River. The southwest end of Coburn drains into Enchanted Pond and Enchanted Stream, then into the Dead River. The northwest side of Coburn drains into Horse Brook and Fourmile Brook, then into the Moose River and the Kennebec. The north end of Coburn drains into Piel Brook, then into Parlin Stream and the Moose River.