In 1785 William Tomison of the Hudson's Bay Company sent Mitchell Oman to build South Branch House at a ford later called Gardepuy's crossing.
In July 1794, following their destruction of Manchester House the year before, one or two hundred Gros Ventres attacked the HBC post.
The Gros Ventres broke in and butchered everyone inside including women and children, except for J. C. Van Dreil who managed to escape in a canoe after hiding in an abandoned cellar for eight hours.
Duncan McGillivray's journal implies that the NWC people were unaware of what was happening at the HBC fort.
Seeing the impossibility of defense or further trade, Louis Chatelain, the master, loaded all his men and goods on canoes and abandoned the fort.