Cahto (also spelled Kato) is an extinct Athabaskan language that was formerly spoken by the Kato people of the Laytonville and Branscomb area at the head of the South Fork of the Eel River. It is one of the four languages belonging to the California Athabaskan cluster of the Pacific Coast Athabaskan languages. Most Kato speakers were bilingual in Northern Pomo and some also spoke Yuki.