It is a tributary of Cupsuptic Lake , an arm of Mooselookmeguntic Lake .
The Kennebago River is a 30 - mile - long ( 48 km ) river in northwestern part of the U.S. state of Maine .
Kennebago River is a tributary of Cupsuptic Lake , an arm of Mooselookmeguntic Lake .
The Kennebago River is a 30 - mile - long ( 48 km ) river in northwestern part of the U.S. state of Maine .