Montana had a cattle trade in the western valleys and foothills since the 1860s as ranches grew up to feed the mining camps, and Texas longhorns had been trailed into Montana as early as 1866. But the era of the cattleman didn’t really begin until the 1880s, when longhorn cattle were trailed north from Texas in great numbers.
Typically, the large “outfits” that brought cattle into Montana at this time were owned by a group of investors who bought shares in herds often numbering in the tens of thousands. Cowboys would herd these longhorns north from Texas, summer them free on the grassy unfenced prairies of Montana, and then round them up, sort them by brand, and sell them to eastern markets. This get-rich-quick scheme worked for many, because with a small investment in the startup animal, low labor costs with the cowboys, and no feed bills to pay, the profitability was great.
Initially, the fattened steers were trailed south into Wyoming to railheads on the Union Pacific. With the construction of the Northern Pacific along the course of the Yellowstone River in 1881–1882, railheads such as Wibaux, Miles City, and Billings became centers for the livestock trade and turned into full-blooded Old West cattle towns. In 1870 there were 48,000 head of cattle in Montana. By 1886, the height of the open-range period, there were 675,000 head.
© W.C. McRae & Judy Jewell from Moon Montana, 7th Edition