U.S. Route 10 in Montana

US 10 in Montana started on the Idaho border in Lookout Pass. As it traveled through the mountains, it traveled through several small towns, including St. Regis, where it intersected Montana Highway 461 (MT 461). From here, it continued east toward Missoula. In the Missoula area, US 10 would intersect US 10A (later MT 200), US 93, US 12, and MT 20 (later MT 200). The route within Missoula still exists and is signed as I-90 Business (I-90 Bus.). US 10 and US 12 ran concurrently east of Missoula until US 12 split off in Garrison. An alternate route (MT 1) split from US 10 in Drummond and rejoined US 10 east of Anaconda. After leaving Anaconda, US 10 would continue to travel east toward Butte. Shortly before entering Butte, US 10 would intersect US 91 (later I-15) and US 91 would travel concurrently with US 10 into downtown Butte.

Before the establishment of the United States Numbered Highway System, a transcontinental road called the Yellowstone Trail ran through Montana. This trail overlapped much of what would become US 10 and later I-90. US 10 completely replaced the Yellowstone Trail in Montana by 1930.[3]

US 10 was one of the first U.S. Highways established in 1926. Over time, it was slowly upgraded to freeway standards after the Interstate Highway System was introduced in 1956. Eventually, the majority of US 10 (except a section later designated MT 2) ran concurrently with the I-90 and I-94. In 1986, the US 10 designation was completely decommissioned in Montana.[2] Many sections of the former route that were not upgraded to freeway standards are now either signed as I-90 Bus., I-94 Bus., as a Montana Secondary Highway, or simply "Old U.S. Highway 10" or some derivative of it.

This list follows the final non-freeway alignment in 1960.[5]

County	Location	mi	km	Destinations	Notes
Mineral	Saltese			US 10 west – Coeur d'Alene, Idaho	Continuation into Idaho
	St. Regis			S-461 to US 10A – Paradise	Southern terminus of S-461
Missoula	Wye			US 93 north / US 10A west – Ravalli, Sandpoint, Idaho	Eastern terminus of US 10A / Western terminus of US 93 concurrency
	Missoula			US 93 south / US 12 east – Stevensville	Eastern end of US 93 concurrency / Western end of US 12 concurrency / Western terminus of US 12
	Milltown			MT 20 east – Great Falls
Granite	Drummond			US 10A east – Anaconda
Powell	Garrison			US 12 east – Helena	Eastern end of US 12 concurrency
Deer Lodge	Warm Springs			MT 48
	Anaconda			US 10A west
Silver Bow	Butte			US 91 south – Dillon	Western end of US 91 concurrency
				US 91 north – Helena	Eastern end of US 91 concurrency
Jefferson	Whitehall			MT 41 south – Twin Bridges
Gallatin	Three Forks			MT 287 south – Yellowstone National Park	Western end of MT 287 concurrency
				MT 287 north – Helena	Eastern end of MT 287 concurrency
				S-286
	Bozeman			US 191	Northern terminus of US 191
Park	Livingston			US 89 south – Yellowstone National Park	Western end of US 89 concurrency
				US 89 north – Great Falls	Eastern end of US 89 concurrency
Sweet Grass	Big Timber			MT 19
Yellowstone	Laurel			US 212 west / US 310 east / S-789	Western end of US 212 concurrency
	Billings			MT 3
				US 87 south	Southern end of US 87 concurrency
				US 87 north	Northern end of US 87 concurrency
Rosebud	Forsyth			US 12	Western end of US 12 concurrency / eastern terminus of US 312
Custer	Miles City			MT 22
				US 212	Northern terminus of US 212
				US 12 east – Baker	Eastern end of US 12 concurrency
Dawson	West Glendive			MT 20S
	Glendive			MT 16
Wibaux	Wibaux			US 10 east – Dickinson, North Dakota	Continuation into North Dakota
1.000 mi = 1.609 km; 1.000 km = 0.621 mi       Concurrency terminus

• U.S. Route 310
• U.S. Route 10 Alternate (Washington–Montana)
• Montana Highway 1