Mullan Road, A historic road, actually a wagon route, across the American Northwest between the Missouri and Columbia rivers, built between 1859 and 1860.

Mullan Road is a wagon road built by U.S. Army troops under Lt. John Mullan between spring 1859 and summer 1860, running from Fort Walla Walla in Washington Territory to Fort Benton on the Missouri River. It was carved 25 feet wide across the Rocky Mountains, and parts remain travelable, including a section near Washtucna, Washington. In the photograph, a dirt track with twin wheel ruts climbs a grassy hill, bordered by dry pale grass and a wire fence with one thick dark wooden post.

Mullan Road was built by U.S. Army troops under Lieutenant John Mullan between spring 1859 and summer 1860, linking Fort Benton on the Missouri with Fort Walla Walla near the Columbia. Floods destroyed long stretches after completion, forcing a reroute in 1861; no maintenance was ever funded. In its first year an estimated 20,000 people, 6,000 horses and mules, 5,000 cattle and 83 wagons used it, until the Northern Pacific Railroad of 1883 offered faster travel.

The road is seen as a symbol of the opening of the American Northwest to settlers and trade. Along certain sections, the original path is still visible in the landscape, giving visitors a direct sense of how people once moved through this remote land.

Some sections of the road are only reachable on foot or with off-road vehicles, so planning ahead and choosing the right gear matters. Weather in the mountains can shift quickly, so sturdy footwear and extra layers are a good idea before setting out.

The Mullan Road was carved by a workforce of more than 200 civilian workers, surveyors, engineers and soldiers under Lieutenant John Mullan, who cut a road 25 feet (7.6 m) wide across the region. Floods wiped out substantial stretches soon after completion in 1860, forcing a rerouting in 1861, and no provision for maintenance was ever made.