Interstate 86 (west)

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 (east). For the former alignment of I-86 east of East Hartford, Connecticut, see Interstate 84 (east).

Interstate 86
Route information
Maintained by ITD
Length:	62.850 mi (101.147 km)
Major junctions
West end:	I-84 / US-30 near Declo
	US-30 / US-91 in Chubbuck
East end:	I-15 in Chubbuck
Highway system
Main route of the Interstate Highway System Main • Auxiliary • Business State Highways in Idaho ← I-84 SH-87 →

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. The highway is the shortest east-west route in the Interstate Highway System which is not a special route.

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

Cassia County, Idaho

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, Idaho

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, while 1-86 continues eastward across the Portneuf River.

Bannock County, Idaho

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.

History

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 designated as part of the Interstate Highway System in 1960 as Interstate 15W. 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.

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.

Exit list

County	Location	Mile	#	Destinations	Notes
Cassia		0.000		I-84 west / US-30 west – Twin Falls	Westbound exit and eastbound entrance
		0.000	1	I-84 east – Ogden	Westbound exit and eastbound entrance
		14.807	15	Raft River Area
Power		20.590	21	Coldwater Area
		28.100	28	Massacre Rocks State Park
		32.620	33	Neeley Area
		36.123	36	I-86 Bus. east / SH-37 – Rockland, American Falls
		40.110	40	I-86 Bus. west / SH-39 – Aberdeen, American Falls
		44.327	44	Seagull Bay
		49.152	49	Rainbow Road
		52.491	52	Arbon Valley
		55.551	56	Pocatello Air Terminal
		58.087	58	US-30 east – West Pocatello	East end of US-30 overlap
Bannock	Chubbuck	61.268	61	US-91 (Yellowstone Avenue) – Chubbuck
		62.526	63	I-15 – Salt Lake City, Blackfoot, Idaho Falls	Eastbound exit and westbound entrance; signed as exits 63A (south) and 63B (north)

External links

• Idaho Highway Index Page (photos of I-86)