Kamiah is a city in Idaho and Lewis counties in the U.S. state of Idaho. The largest city in Lewis County, it extends only a small distance into Idaho County, south of Lawyer Creek. The population was 1,295 at the 2010 census. The city lies in the narrow valley of the Clearwater River; downstream are Orofino and Lewiston, at the confluence with the Snake River. The Kamiah area has been inhabited by the Nez Perce tribe for centuries.