Kennebago Divide stands within the watershed of the upper Androscoggin River, which drains into Merrymeeting Bay, the estuary of the Kennebec River, and then into the Gulf of Maine. The southeast side of Kennebago Divide drains into Bear Brook, and thence into the Kennebago River, then into Cupsuptic Lake, through a series of lakes into the Rapid River and Umbagog Lake, the source of the Androscoggin River. The south end of Kennebago Divide drains into Wiggle Brook, then into the Kennebago River. The northwest side of Kennebago Divide drains into Porter Brook and the Cupsuptic River, then into Cupsuptic Lake.