Expansion of the cattle industry resulted in the need for additional open range. Thus many ranchers expanded into the northwest, where there were still large tracts of unsettled grassland. Texas cattle were herded north, into the Rocky Mountains and Dakotas. In 1866, Nelson Story used the Bozeman Trail to successfully drive about 1000 head of Longhorn into the Gallatin Valley of Montana. Individual cattle barons such as Conrad Kohrs built up significant ranches in the northern Rockies. In 1866, Kohrs purchased a ranch near Deer Lodge, Montana from former Canadian fur trader Johnny Grant. At its peak, Kohrs owned 50,000 head of cattle, grazing on 10 million acres (4 million hectares) spread across four states and two Canadian Provinces, and shipped 10,000 head annually to the Union Stock Yards in Chicago.