 American Fur spent years negotiating, and finally met McKenzie's demands in 1827 to buy Columbia Fur.It was renamed the "Upper Missouri Outfit" division of American Fur, and in 1828, McKenzie went up the river to lead the fur trade, building Fort Union near the confluence of the Missouri and Yellowstone Rivers.Fort Union was ideally situated to dominate the final years of the beaver pelt trade and the beginning of the buffalo hide trade, and many tribes dealt with McKenzie.