U.S. 12

U.S. 12

Traveling 598 miles across the Glacier State, U.S. 12 enters Montana from Lolo Pass to the west and leaves to the east at Little Missouri National Grassland into North Dakota. Following the West Fork of Lolo Creek, U.S. 12 travels northward from Lolo Pass to Lolo Hot Springs, where the two forks of Lolo Creek come together. U.S. 12 leads east from there alongside Lolo Creek to the community of Lolo and the beginning of a 7.5 mile long overlap with U.S. 93 north into Missoula.

Once in Missoula, U.S. 12 splits with a Business Route into Downtown while staying east to the University of Montana. Leaving Montana's second largest city, U.S. 12 combines with Interstate 90 for 68 miles to Drummond and Garrison. The US highway parallels the Little Blackfoot River east from I-90 to MacDonald Pass across the General Eisenhower Range, becoming a four lane highway into Helena.

Within the capital city, U.S. 12 follows Euclid Avenue east and combines with Business Loop I-15 south along an L-shaped route from the business district to I-15 at Exit 192. U.S. 287 joins U.S. 12 east through East Helena, Townsend and the south end of Canyon Ferry Lake. U.S. 287 continues south from there to Three Forks and I-90 while U.S. 12 resumes eastward 28 miles across the Big Belt Mountains to U.S. 89.

U.S. 12/89 overlap eight miles northward to White Sulphur Springs and another three miles east to their separation. U.S. 89 heads into the Little Belt Mountains en route to Great Falls while U.S. 12 winds east to Cherkerboard and Harlowton. Harlowton includes a two mile overlap with U.S. 191, which runs south to Big Timber and north to Lewiston.

Leaving the high mountains for good, U.S. 12 advances 68 miles east to Shawmut, Ryegate and Roundup, where there is a short overlap with U.S. 87. U.S. 12 follows the Musselshell River east from Roundup 36 miles to Rosebud County. Bending back southward, U.S. 12 enters Hammond Valley along the Yellowstone River and joins Interstate 94 east at Forsyth for a 47 mile long concurrency to Miles City.

The final 88 miles of U.S. 12 takes the route east from I-94 at Exit 141 across The Pine Hills to Plevna and Baker. U.S. 12 departs the state west of Marmarth, North Dakota.

U.S. 12 Montana Guides

Historic U.S. 312

Until 1974, U.S. 312 ran south from Miles City along MT 59 to U.S. 212 at Broadus. The former route overlapped with both U.S. 10 and U.S. 12 west from Miles City to Forsyth, and with U.S. 10 west from Forsyth to I-94 at Exit 23. Following the completion of Interstate 94, U.S. 312 followed old U.S. 10 along a Northern Pacific Railroad line west from I-94/U.S. 10 to Worden and U.S. 87 on the north side of Billings. U.S. 312 joined U.S. 87 southward to its 1962 end point in Billings.

Between 1960 and 1962, U.S. 312 continued west from Billings to Laurel, Cooke City and the Northeast Entrance of Yellowstone National Park. This route was discontinued in favor of a westward extension of U.S. 212.

Photo Credits:

Connect with:

Page Updated Friday October 25, 2013.