Interstate 86 (Idaho)

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This article is about the Interstate highway located in southeastern Idaho. For the Interstate highway that runs through New York and Pennsylvania, see Interstate 86 (Pennsylvania–New York). For the former alignment of I-86 east of East Hartford, Connecticut, see Interstate 84 (Pennsylvania–Massachusetts).

Interstate 86 marker

Interstate 86
Route information
Maintained by ITD
Length: 62.850 mi[1] (101.147 km)
Major junctions
West end: I-84 / US 30 near Declo

SH 37 in American Falls
SH 39 in American Falls
US 30 in West Pocatello

US 91 in Chubbuck
East end: I-15 in Chubbuck
Highway system

Interstate 86 (I-86) is an intrastate Interstate Highway, located entirely within the state of Idaho. It runs 63 miles (101.4 kilometers) from an intersection with Interstate 84 located approximately 7 miles (11.3 kilometers) east of Declo in rural Cassia County, to an intersection with Interstate 15 at Pocatello. Interstate 86 connects the major eastern Idaho cities of Pocatello and Idaho Falls with the Twin Falls area and other cities in the state's Magic Valley region. Prior to the designation of Interstate 2 on May 30, 2013, Interstate 86 in Idaho was the shortest east-west route in the Interstate Highway System which is not a special route.[2]

I-86 was proposed to become designated as Interstate 82N, but was eventually designated as Interstate 15W, instead.

Besides being short, the area Interstate 86 passes through is very desolate. Pocatello, Chubbuck and American Falls are the only incorporated settlements located on the highway. Between American Falls and Pocatello I-86 passes through a portion of Fort Hall Indian Reservation.

Route description[edit]

Exit from I-86 to Chubbuck

Cassia County[edit]

Running east, I-86 begins at an interchange with Interstate 84 and U.S. Route 30 in rural Cassia County; it becomes concurrent with US 30 at this interchange, and remains so for much of its route. The highway runs east through a rural and largely undeveloped section of Cassia County; it has no exits in its first 14 miles. After this section, I-86 crosses the Raft River and reaches an exit with Yale Road in the community of Raft River.

Power County[edit]

The highway continues east into Power County, running to the south of the Snake River. It reaches its next exit, at Barkdull Road in Coldwater, around milepost 21. I-86 heads northeast along the river to an exit at Massacre Rocks State Park. The highway continues northeast to meet Rock Creek Road in Neeley. Past Neeley, I-86 reaches an interchange with Idaho State Highway 37, which runs south to Rockland, and Interstate 86 Business, a business loop serving American Falls.

I-86 bypasses American Falls to the southeast, meeting its business loop and Idaho State Highway 39 east of the city near American Falls Airport. The highway runs south of the American Falls Reservoir to its next exit at Ramsey Road near Seagull Bay. Past this exit, the route enters the Fort Hall Indian Reservation. After passing another exit at Rainbow Road near the eastern edge of the reservoir, I-86 heads eastward toward Pocatello. It serves exits at Arbon Valley and the Pocatello Air Terminal before leaving the Fort Hall Indian Reservation. US 30 leaves I-86 at the next exit to the southeast, where the latter continues eastward across the Portneuf River.

Bannock County[edit]

The highway crosses into Bannock County and enters the city of Chubbuck, where it intersects U.S. Route 91. I-86 briefly passes through Pocatello without an interchange in the city and terminates at Interstate 15 outside the Pocatello city limits.[1][3]


The route of Interstate 86 largely derives from a portion of U.S. Route 30N constructed in the 1920s, which in Idaho originally ran from Burley to a point on the Wyoming state line near Montpelier. Present-day Interstate 86 was proposed to become part of the Interstate Highway System as Interstate 82N,[4] but was eventually designated in 1960 as Interstate 15W.[5] U.S. Route 30N was designated as part of U.S. Route 30 in 1972. Interstate 86 continues to run concurrently with U.S. Route 30 for almost its entire length.[6]

In the late 1970s, the American Association of State Highway and Transportation Officials decided it was better to have duplicate numbers in different parts of the country instead of having suffixes. There was also an Interstate 15E in California at the time. Interstate 15W was re-designated as Interstate 86 in 1980.[7]

Exit list[edit]

County Location mi[1] km Exit Destinations Notes
Cassia Declo 0.000 0.000 I-84 west / US 30 west – Twin Falls West end of US-30 overlap
0.000 0.000 1 I-84 east – Ogden, UT, Salt Lake City, UT Westbound exit and eastbound entrance, western terminus; I-84 exit 222
14.807 23.830 15 Raft River Area
Power 20.590 33.136 21 Coldwater Area
28.100 45.223 28 Massacre Rocks State Park
32.620 52.497 33 Neeley Area
American Falls 36.123 58.134 36 I-86 Business Loop east / SH 37 – Rockland, American Falls West end of Business Loop 86
40.110 64.551 40 I-86 Business Loop west / SH 39 – Aberdeen, American Falls East end of Business Loop 86
44.327 71.337 44 Seagull Bay
49.152 79.102 49 Rainbow Road
52.491 84.476 52 Arbon Valley
55.551 89.401 56 Pocatello Air Terminal
58.087 93.482 58 US 30 east – West Pocatello East end of US-30 overlap
Bannock Chubbuck 61.268 98.601 61 US 91 (Yellowstone Avenue) – Chubbuck
62.526 100.626 63 I-15 – Salt Lake City, Idaho Falls Eastern terminus and signed as exits 63A (south) and 63B (north); I-15 exit 72
1.000 mi = 1.609 km; 1.000 km = 0.621 mi


  1. ^ a b c "Interstate 86 Milepoint Log". Idaho Transportation Department. Retrieved 28 February 2011. 
  2. ^ Idaho Transportation Department (accessed 3 January 2012)
  3. ^ "Overview map of Interstate 86". Google Maps. Google, Inc. Retrieved 28 February 2011. 
  4. ^ Official Route Numbering for the National System of Interstate and Defense Highways (JPG) (Map). American Association of State Highway and Transportation Officials. August 14, 1957. Retrieved May 4, 2014. 
  5. ^ Idaho Highways (accessed 3 January 2012)
  6. ^ U S Roads --- Idaho (accessed 3 January 2012)
  7. ^ Idaho Highways (accessed 3 January 2012)

External links[edit]

Route map: Bing / Google

KML is from Wikidata