Asotin is the former site of a Nez Perce winter camp and is named after the eels that were plentiful in Asotin Creek (Native name Has su tun).

The name Asotin was reduced from Has-Hu-Tin (meaning eel) to Hassotin, then to Asotin. The town was given the present spelling by an act of the Legislature in 1886. In early history, there were two distinct towns, Asotin and Assotin City. Asotin County was carved from Garfield County. October 1st of 1883, Asotin was named the County seat, which in years to come created considerable controversy between Asotin and Clarkston. Before the coming of the white man, Asotin was the winter camp for the Nez Perce Indians. It was an ideal hunting and fishing spot. The Indians gathered here because, as they said, “no wind, no snow.” They often held their Pow-Wows with other northwestern tribes on the banks of the Snake River.