The distinct “Point of Rocks,” towering over a scenic bend in the Clark Fork River, is a pleasant distraction for Interstate motorists making their way through western Montana. But the feature also provides a unique glimpse into the region’s transportation history. An aboriginal trail once traversed the narrow canyon; it later became the site of the Mullan Road, a pair of transcontinental railroads, the Yellowstone Trail, U.S. Highway 10, and, finally, Interstate 90. Unlike places where development has erased evidence of historic paths, this challenging stretch forced road builders to blast their way through canyon rock and forever leave their mark. It’s a story in stone that not only tells a tale of the development of the American West, but also reveals the basic challenges road builders faced in setting their paths through Montana’s rugged landscape.

In 1860, Lieutenant John Mullan and his team of some 250 men encountered the features he christened “Point of Rocks” and the “Big Side Cut.” His crew had surpassed the halfway mark on their 624-mile push eastward from Fort Walla Walla, Washington, to Fort Benton, Montana, but the rock features proved to be the most daunting of the entire road. According to Mullan, “in order to obtain the practicable elevation on account of the abrupt rocky face of the spurs, I carried the line up a ravine, until gaining 1,000 feet; I wound around the mountain sides, making the re-entering angles by gentle curves, until the entire six miles was completed.” The stretch took the Mullan crew six weeks to build. By contrast, it took just another six weeks to cover the final 250 miles to Fort Benton.

The Chicago, Milwaukee, St. Paul and Pacific Railroad (Milwaukee Road), built in 1908, took a different line through the Point of Rocks, blasting and tunneling its way to maintain the gradual grades and curves required of rail transportation. It added towering bridges over the Clark Fork to avoid the steep grades associated with Mullan’s Big Side Cut. Today, visitors can follow the paths of the Mullan Road and Milwaukee Road through Point of Rocks and find interpretive signs telling of its history. It’s an opportunity to take it all in, as transportation historian Jon Axline explained, “From one point a sojourner can look out across the grades of two transcontinental railroads (the Northern Pacific and Milwaukee), the old Yellowstone Trail, U.S. highway 10, and Interstate 90.” To access the area from I-90, take Exit 75 and follow the North Frontage Road 2 miles and cross the bridge over Mountain Creek. Park in a gravel pit on your left and walk through the gate along the old Milwaukee Railroad grade.

Credits and Sources:

Axline, Jon. “‘A Wonderful Piece of Engineering’: The Point of Rocks Segment of the Mullan Road and the Milwaukee Road Railroad in Mineral County, Montana.” The Journal of the Society of Industrial Archaeology 37, no. ½, Theme Issue: IA in Montana (2011): 29–42.

------. “Mullan’s Point of Rocks: Preserving Transportation History,” Montana: The Magazine of Western History 49, no. 4, Special Transportation Issue (Winter 1999): 90–91.

------. “Point of Rocks Historic Transportation Corridor.” United States Department of the Interior, National Park Service, National Register of Historic Places Inventory—Nomination Form, July 24, 2009

Briggeman, Kim. “Retracing History: Original Mullan Road Full of Rugged Tales.” Missoulian, May 1, 2008.

Mullan, Captain John. Report of the Construction of a Military Road from Fort Walla Walla to Fort Benton. Reprint of 1863, Government Printing Office Document. Fairfield, WA: Ye Galleon Press, 1994.

Historic portrait of Captain John Mullan courtesy of the Mineral County Historical Museum, Superior, MT.

Contemporary photographs courtesy of Historical Research Associates, Inc.