the snake river archaeological district is an archaeological area located in nez perce county, idaho, and asotin county, washington, and centered on the snake river, which divides the two states. the area includes a number of sites inhabited by the nez perce people, who used it as a fishing ground and a winter campsite. settlement in the area stretches from roughly 6000 b.c. to the 20th century a.d. several hundred pictographs are part of the area, usually painted at village sites.