| Mullan Pass | |
|---|---|
 Historical marker placed at Mullan Pass. | |
| Elevation | 5,902 ft (1,799 m) |
| Traversed by | Austin-Mullan Pass Road and BNSF Railway (via Mullan Pass Tunnel). |
| Location | Lewis and Clark / Powell counties, Montana, U.S. |
| Range | Rocky Mountains |
| Coordinates | 46°38′36″N 112°18′50″W / 46.6434°N 112.3138°W |
  Mullan Pass Location in Montana, U.S.  Mullan Pass Mullan Pass (the United States) | |
Mullan Pass is a mountain pass in the western United States, in the Rocky Mountains of Montana. It sits on the Continental Divide on the border between Powell and Lewis and Clark counties at 5,902 feet (1,799 m) above sea level. Located in the Helena National Forest, the pass is thirteen miles (20 km) west of the city of Helena.
The Northern Pacific Railway (NP) used the pass for its line from Logan to Garrison via Helena, built in 1883. This line was the NP's primary freight route and was also used by their secondary passenger train, the Mainstreeter. The NP also built an alternate line over Homestake Pass, which was used by their primary passenger train, the North Coast Limited. The rail line at Mullan Pass is currently operated by BNSF Railway; it crosses under the pass and the continental divide at 5,566 feet (1,697 m) via the 3,426-foot (0.65 mi; 1.04 km) Mullan Tunnel.
The pass was named after Lieutenant John Mullan, the U.S. Army engineer who first crossed the pass on March 22, 1854, and later supervised construction of the Mullan Road, the first road over the pass, in 1860.