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Interstate Highways of the Idaho State Highway System

Interstate 15 marker

Interstate 184 marker

Interstate 90 Business marker

Typical Interstate highway markers
Interstate Highways highlighted in red
System information
Maintained by ITD
Length611.31 mi [1] (983.81 km)
Formed1956
Highway names
InterstatesInterstate n (I-n)
US HighwaysU.S. Highway n (US-n)
StateIdaho State Highway n (SH-n)
System links
  • Idaho State Highway System

The Interstate Highways in Idaho are the segments of the Dwight D. Eisenhower National System of Interstate and Defense Highways owned and maintained by the Idaho Transportation Department (ITD) in the U.S. state of Idaho. The state has five Interstate Highways that total approximately 611 miles (983 km) in length. [1]

Mainline highways

Number Length (mi) [2] Length (km) Southern or western terminus Northern or eastern terminus Formed Removed Notes
I-15 196.000 315.431 I-15 near Woodruff I-15 at Monida Pass 01957-01-011957 current  
I-15W 62.850 101.147 I-84 / US 30 near Declo I-15 in Chubbuck 01957-01-011957 01978-01-011978 Became I-86
I-80N 275.650 443.616 I-84 near Fruitland I-84 near Black Pine 01957-01-011957 01980-01-011980 Became I-84
I-84 275.650 443.616 I-84 near Fruitland I-84 near Black Pine 01980-01-011980 current Designated as I-80N until 1980
I-86 62.850 101.147 I-84 / US 30 near Declo I-15 in Chubbuck 01978-01-011978 current Designated as I-15W until 1978
I-90 73.888 118.911 I-90 in State Line I-90 at Lookout Pass 01957-01-011957 current  
I-180N 3.620 5.826 I-84 / US 30 in Boise US 20 / US 26 in Boise 01970-01-011970 01979-01-011979 Became I-184
I-184 3.620 5.826 I-84 / US 30 in Boise US 20 / US 26 in Boise 01979-01-011979 current Designated as I-180N until 1979, completed in 1990
  •       Former

Business routes

Number Length (mi) [2] Length (km) Southern or western terminus Northern or eastern terminus Formed Removed Notes
I-15 BL 4.338 6.981 I-15/ US 91 exit 44 near McCammon I-15/ US 30/US 91 exit 47 in McCammon — —
I-15 BL 1.000 1.609 I-15/US 30/US 91 exit 57 in Inkom I-15/US 30/US 91 exit 58 in Inkom — —
I-15 BL 5.560 8.948 I-15/US 30/US 91 exit 67 in Pocatello I-15 exit 69 in Pocatello — — US 30 and US 91 branches off I-15 at its southern end
I-15 BL 4.802 7.728 I-15 exit 89 southwest of Blackfoot I-15/ US 26 exit 93 in Blackfoot — — I-15 and US 26 begin concurrency at northern end
I-15 BL 7.230 11.636 I-15/US 26 exit 116 near Idaho Falls I-15/ US 20 Bus. exit 118 in Idaho Falls — — Concurrent with Us 26 at south end and US 20 Bus. at north end
I-84 BL 12.557 20.209 I-84/US 20/US 26/US 30 exit 27 in Caldwell I-84/US 30/ SH-55 exit 38 in Nampa — —
I-84 BL — — I-84/US 30 exit 49 west of Boise I-84/US 20/US 26/US 30 exit 54 in Boise — — Now part of I-184, US 20, and US 26
I-84 BL 5.985 9.632 I-84/US 20/US 26/US 30 exit 90 near Mountain Home I-84/US 26/US 30 exit 99 near Mountain Home — —
I-84 BL — — I-84/US 26/US 30/ SH-78 exit 112 in Hammett I-84/US 26/US 30 exit 114 near Hammett — — Runs concurrent with SH-78 at west end
I-84 BL 1.425 2.293 I-84/US 26/US 30 exit 120 in Glenns Ferry I-84/US 26/US 30 exit 121 in Glenns Ferry — —
I-84 BL 3.518 5.662 I-84/US 26/US 30 exit 137 near Bliss I-84/US 26 exit 141 in Bliss — — Runs concurrent with US 30 near whole length. Road continues as US 26 at east end
I-84 BL 6.56 10.56 I-84/ SH-27 exit 208 near Burley I-84/US 30/ SH-24 near Heyburn — — Entirely concurrent with SH-27 at west end then US 30 to east end. Road continues as SH-24
I-86 BL 6.475 10.421 I-86/US 30/ SH-37 exit 36 near Neeley I-86/US 30/ SH-39 exit 40 in American Falls 01972-01-011972 current Concurrent with SH-39 toward east end
I-90 BL 5.640 9.077 I-90 exit 2 west of Post Falls I-90 exit 6 in Post Falls — —
I-90 BL 3.834 6.170 I-90 exit 11 near Coeur d'Alene I-90 exit 15 in Coeur d'Alene — —
I-90 BL 1.4 2.3 I-90 exit 49 near Kellogg I-90 exit 51 in Kellogg — —
I-90 BS 3.966 6.383 I-90 exit 57 in Osburn E. Mullan Ave. in downtown Osburn — — Originally a business loop that ran from exit 57 to exit 60 to Silverton via Silver Valley Road. Split into two separate spurs
I-90 BS 0.12 0.19 I-90 exit 60 in Silverton Silver Valley Rd south of Silverton — — Part of original loop that once ran from I-90 exit 57 in Osburn to exit 60 in Silverton via Silver Valley road. Split into two separate spurs
I-90 BL 1.243 2.000 I-90 exit 61 near Wallace I-90 exit 62 in Wallace — — Originally part of I-90 that contained a traffic signal before entering Wallace. Became I-90BL when I-90 was rerouted north as a full freeway
I-90 BL 1.000 1.609 I-90 exit 68 in Mullan I-90 exit 69 near Mullan — —
  •       Former

See also

References

  1. ^ a b "National Highway Freight Network Map and Tables for Idaho". Federal Highway Administration. 2015. Retrieved December 11, 2022.
  2. ^ a b "Milepoint Logs". Idaho Transportation Department. Retrieved February 15, 2017.

External links

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