South Branch House, Heritage site and trading post remains on South Saskatchewan River, Canada.

South Branch House is a Provincial Historic Site on the right bank of the South Saskatchewan River, about 10 miles west of Saint Louis and 10 miles north of Batoche, with a hill behind it. The ruins of the Hudson's Bay Company post are marked by a marker, and minor archaeological work continues at the site.

South Branch House was built in 1785 by Mitchell Oman for the Hudson's Bay Company at a ford later called Gardepuy's crossing, and David Thompson served there as a clerk in 1786/87. In July 1794 one or two hundred Gros Ventres attacked the post, killing the officers Magnus Annal and Hugh Brough and everyone inside except J. C. Van Dreil, who escaped by canoe. Both companies rebuilt about 6 miles upstream in 1805, and after the 1821 merger the HBC ran the post until 1870.

The site shows archaeological evidence of trade interactions between European merchants and First Nations communities during the competitive fur trading period. These exchanges shaped daily life at the location and reveal how different cultures engaged and conducted business together.

The site lies about 20 miles east of Fort Carlton, 10 miles west of Saint Louis and 10 miles north of Batoche, on the right bank of the South Saskatchewan River with a hill behind it. A marker stands at the ruins, where minor archaeological work continues. The ground is unexcavated in places, so watch your footing.

In 1786–87 the explorer David Thompson served as one of Mitchell Oman's clerks at South Branch House, years before he mapped much of western Canada. The post stood at a ford later called Gardepuy's crossing, and rival traders moved their posts 400 yards downstream to the opposite bank.