Kamiah is a city in Lewis and Idaho 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, up from 1,160 in 2000. The city lies in the narrow valley of the Clearwater River; downstream are Orofino and Lewiston, at the confluence with the Snake River.