The Big Horn Gun is one of Montana’s most prized historical possessions, however most Montanans do not have any idea that it exists. It is a cannon thought to have been cast in the late 1700’s and possibly used in the Mexican-American War. Today it is located in the Gallatin County Museum in Bozeman, housed in the original county jail on Main Street.
The gun is thought to have arrived in the Montana territory sometime around 1870, with and expedition heading for the Black Hills from Cheyenne, Wyoming. Part of that group instead came down the Big Horn River and brought the gun with them. That is the reason for its name.
The gun eventually was taken up the Yellowstone River and then overland to Bozeman. That is where its notoriety really began, as in the fall of 1873 a group of men from around the region heard talk of a gold strike on the Rosebud drainage of Eastern Montana, a region controlled by hostile Sioux, Cheyenne and Arapahoe Natives. Talk of this discovery resulted in the formation of an expedition into eastern Montana by 174 of these men and preparations were made to set out in the early part of the following year.
Prior to their exit from Bozeman, the men of the expedition were treated to an oyster feed at the expense of the merchants of the growing community, as the efforts of this expedition could aid in the development of their town and the growth of the Territory. It is said that the oyster cans were used as casings for canister rounds for the gun, as the men had no ammunition for it. It is estimated that they made 150 such rounds which were full of shards of metal and proved to be very deadly at short range.
In February of 1874, the party left Bozeman, under the guise of the ‘Yellowstone Wagon Road Expedition”, hoping to deflect the real aim of their endeavor. After having reached the Rosebud in April of that year, the group of gold seekers met heavy resistance from the Natives in skirmishes ranging from Green Leaf Creek, near Colstrip, over the Davis Creek divide above Busby, toward the base of the Big Horns through the Lodge Grass country and on to the old Bozeman Trail.
This group of gold seekers never found El Dorado, but they did manage to make it through the region with only losing one man while inflicting fairly heavy casualties on the Natives. Given this information, it is easy to see why military commanders, such as George Armstrong Custer, would assume those tribes would be easy to force into capitulation. However, as history would prove a mere two years later, the Sioux, Cheyenne and Arapahoe were more of a forced to be reckoned with than they thought, and the Seventh Cavalry would face a stunning defeat by them at the Little Big Horn.