Mattole, or Mattole–Bear River, is an extinct Athabaskan language language once spoken by the Mattole and Bear River peoples of northern California. It is one of the four languages belonging to the California Athabaskan cluster of the Pacific Coast Athabaskan languages. It was found in two locations: in the valley of the Mattole River, immediately south of Cape Mendocino on the coast of northwest California, and a distinct dialect on Bear River, about 10 miles to the north.