| Montana Interstates |
Description :
Runs from the MT/ID Border in Monida Pass to the MT/AB Border at Sweetgrass, MT for 396.03 miles
Multiplexes :
I-90 from Exit 121 to Exit 129 (7.65 miles)
US 89 from Exit 278 to Exit 290
US 287 from Exit 192 to Exit 228
Major Cities :
Dillon, Butte, Helena, Great Falls
Business Routes :
Dillon, Butte, Helena, Great Falls, Conrad, Shelby
Spurs from I-15 :
I-115 in Butte
I-315 in Great Falls
History :
Part of 1956 plan
I-15's routing follows former US 91.
Description :
Runs from the MT/ID Border at Lookout Pass to the MT/WY Border near
Aberdeen, MT for 551.68 miles
Multiplexes :
I-15 from Exit 219 to Exit 227 (7.65 miles)
US 12 from Exit to Exit 175
US 87 from Exit 452 to the MT/WY Border
US 89 from Exit 332 to Exit 340
US 191 from Exit 298 to Exit 367
US 212 from Exit 434 to Exit 510
MT 200 from Exit 96 to Exit 109
Major Cities :
Missoula, Butte, Bozeman, Billings
Business Routes :
Missoula, Deer Lodge, Butte, Bozeman, Livingston, Timber, Laurel, Billings, Hardin
Spurs from I-90 :
None
History :
Part of 1956 plan
I-90's routing follows former US 10 west from Billings.
Description :
Runs from I-90 at Billings to the MT/ND Border near Wibaux, MT for 249.15 miles
Multiplexes :
US 12 from Exit 93 to Exit 141
Major Cities :
Billings, Miles City, Glendive
Business Routes :
Hysham, Forsyth, Miles City, Glendive, Wibaux
Spurs from I-94 :
None
History :
Part of 1956 plan
I-94 follows former US 10 east from Billings.
Description :
Runs from I-90 / I-15 into Butte for 1.19 miles
Multiplexes :
Business I-90 / I-15 - Entire Route
Major Cities :
Butte
Business Routes :
None
History :
Approved and signed in the 1960's.
Description :
Runs from I-15 into Great Falls for 0.83 miles
Multiplexes :
Business I-15 / US 87 - Entire Route
Major Cities :
Great Falls
Business Routes :
None
History :
Approved in the 1960's, not signed.