Grafton Notch is a notch, or mountain pass, located in Oxford County, Maine. The notch demarks the northeastern end of the Mahoosuc Range, and thus of the White Mountains. Maine State Route 26 passes through the notch. North of the drainage divide, the notch drains into the Swift Cambridge River, then into the Dead Cambridge River and Umbagog Lake, the source of the Androscoggin River, which drains into Merrymeeting Bay, the estuary of the Kennebec River, and thence into the Gulf of Maine. To the south, the notch drains into the Bear River, then into the Androscoggin.