Cantonment Jordan in Montana was a temporary winter camp established by Lieutenant John Mullan in 1859. Mullan, a soldier, explorer, civil servant, and topographical engineer, was tasked with surveying and building a military road from Fort Benton, Montana to Walla Walla, Washington.
Commanding a workforce of more than 200, including civilian workers, surveyors, engineers, and soldiers, Mullan and his crew had cut through about 80 miles of forest and mountains, when Mullan called for a halt near present-day De Borgia, Montana. The men then began to construct a winter camp that was comprised of residential huts, a log cabin office, and a storehouse, surrounded by a stockade and four blockhouses. That winter was incredibly harsh, with the temperature plunging below -40 on December 5, 1859, with five feet of snow. January 1860 was no better with snow accumulating up to seven feet. Frostbitten feet were common and 25 soldiers came down with scurvy, after eating too much salted meat and too few vegetables.
Making matters worse, most of the crew’s cattle, horses, and mules died. After butchering the few cattle that survived, a few men were detailed to herd the remaining horses and mules to the Bitterroot Valley, where temperatures would be warmer and the snow was not as deep. However, none of the animals survived the 100-mile trek.
In the meantime, a supply train was sent out to Cantonment Jordan with food and clothing. However, when it got close the train had to leave many supplies at the foot of the pass because the exhausted animals could not continue. Mullan then ordered his men to build 20 sleds, and the supplies were manually hauled to the camp.
Despite the incredible hardship, Mullan kept his men working with little complaint. The camp was abandoned in the spring of 1860, and the men continued to work on the road.
After two years of work, Mullan and his men completed the 25-foot-wide road across 611 miles through dense forests, over mountains, and across marshlands and raging rivers. When it was completed in 1862, the Mullan Military Road became the first wagon road to traverse the Rocky Mountains into the inland Northwest, and Mullan was promoted to the rank of captain.
The site of Cantonment Jordan was located two miles east of De Borgia, Montana.