Fort Ash (Fort de la Freniere)
The first fur post established on the river was Fort Ash.
Canadian explorer David Thompson spent about two days in the region in December of 1797, on his way south to Mandan country. He recalled passing by “the old trading post called the Ash House from the plenty of those fine trees. It had to be given up from it being too open to the incursions of the Sioux."