| Interstate Highways of the Montana Highway System | |
|---|---|
Typical Interstate highway markers used for Interstate 90, Interstate 115, and Business loop 94 in Montana
| |
Interstate Highways highlighted in red
| |
| System information | |
| Maintained by MDT | |
| Highway names | |
| Interstates | Interstate n (I-n) |
| US Highways | U.S. Highway n (US n) |
| State | Montana Highway n (MT n) |
| Secondary: | Secondary Highway n (S-n) |
| System links | |
The Interstate Highways in Montana are the segments of the Dwight D. Eisenhower National System of Interstate and Defense Highways owned and maintained by the Montana Department of Transportation (MDT) in the U.S. state of Montana.
The state's Interstate highways, totaling 1,198 miles (1,928 km), were built between 1956 and 1988 at a cost of $1.22 billion. 95 percent of the system serves rural areas, the highest proportion of any state under Interstate program.[1] The entire Interstate system in Montana was designated as the Purple Heart Trail in 2003.[2]
| Number | Length (mi)[3] | Length (km) | Southern or western terminus | Northern or eastern terminus | Formed | Removed | ||
|---|---|---|---|---|---|---|---|---|
 I-15
|
396.03 | 637.35 | I-15 near Monida | Hwy 4atSweetgrass | — | — | ||
 I-90
|
551.68 | 887.84 | I-90 near Mullan, ID | I-90 / US 87 near Ranchester, WY | — | — | ||
 I-94
|
249.15 | 400.97 | I-90atBillings | I-94 near Beach, ND | — | — | ||
 I-115
|
1.19 | 1.92 | I-15 / I-90inButte | Downtown Butte | — | — | ||
 I-315
|
0.83 | 1.34 | I-15 / US 89 / MT 200inGreat Falls | Downtown Great Falls | — | — | ||
| Number | Length (mi) | Length (km) | Southern or western terminus | Northern or eastern terminus | Formed | Removed | Notes | |
|---|---|---|---|---|---|---|---|---|
 I-15 BL
|
— | — | — | — | — | — | Serves Dillon | |
| I-15 BL
|
— | — | — | — | — | — | Serves Butte | |
| I-15 BL
|
— | — | — | — | — | — | Serves Helena | |
| I-15 BL
|
— | — | — | — | — | — | Serves Great Falls | |
| I-15 BL
|
— | — | — | — | — | — | Serves Shelby | |
 I-90 BL
|
— | — | — | — | — | — | Serves Alberton | |
| I-90 BL
|
— | — | — | — | — | — | Serves Missoula | |
| I-90 BL
|
— | — | — | — | — | — | Serves Deer Lodge | |
| I-90 BL
|
— | — | — | — | — | — | Serves Butte | |
| I-90 BL
|
— | — | — | — | — | — | Serves Bozeman | |
| I-90 BL
|
— | — | — | — | — | — | Serves Livingston | |
| I-90 BL
|
— | — | — | — | — | — | Serves Big Timber | |
| I-90 BL
|
— | — | — | — | — | — | Serves Laurel | |
| I-90 BL
|
— | — | — | — | — | — | Serves Billings | |
| I-90 BL
|
— | — | — | — | — | — | Serves Hardin | |
 I-94 BL
|
— | — | — | — | — | — | Serves Miles City | |
| I-94 BL
|
— | — | — | — | — | — | Serves Glendive | |
Media related to Interstate Highways in Montana at Wikimedia Commons
