Baldpate Mountain is within the watershed of the Androscoggin River, which drains into Merrymeeting Bay, the estuary of the Kennebec River, and then into the Gulf of Maine. The northwest side of Baldpate Mountain drains into the Swift Cambridge River, then into the Dead Cambridge River and Umbagog Lake, the source of the Androscoggin River. The southeast and southwest sides of Baldpate drain into the Bear River, then into the Androscoggin. The northeast side of Baldpate Mtn. drains into the West Branch of the Ellis River, then into the Androscoggin.