Interstate 90 in Idaho

Interstate 90
Route information
Maintained by ITD
Length:	73.888 mi[1] (118.911 km)
Major junctions
West end:	I‑90 at the Washington state line
	SH-41 in Post Falls US-95 in Coeur d'Alene SH-97 near Coeur d'Alene SH-3 near Cataldo SH-4 in Wallace
East end:	I‑90 at the Montana state line
Highway system
Interstate Highway System Main Auxiliary Suffixed Business State Highways in Idaho ← US-89 US-91 →

In the U.S. state of Idaho, Interstate 90 has a 74-mile-long (119 km) routing in the panhandle. Traveling east from Spokane, Washington, I-90 passes through Post Falls and Coeur d'Alene, over Fourth of July Summit, and through the Silver Valley before entering Montana at Lookout Pass.

I-90 is a major east-west freeway route in northern Idaho.^[2] I-90 is the third longest stretch of Interstate highway in Idaho. Interstate 84 and Interstate 15 are longer. Interstate 86 and Interstate 184 are shorter. I-90 is the only coast-to-coast Interstate in Idaho.

Route description

Interstate 90 enters Idaho and Kootenai County just east of the Spokane River bridge near the community of State Line, the smallest city in Idaho. It proceeds east through Post Falls to Coeur d'Alene, the county seat, and meets U.S. Route 95. I-90 turns southeast and passes north of downtown, which is accessible via an Interstate Business Loop, and Lake Coeur d'Alene. It continues east-southeast to Fourth of July Summit at an elevation of 3,081 feet (939 m) and down to Cataldo, home to the Old Cataldo Mission built 163 years ago in 1853.

Shortly after leaving Cataldo, I-90 enters Shoshone County and passes through or near the communities of Pinehurst, Kellogg, Osburn, Wallace, and Mullan. I-90 leaves the county and state at Lookout Pass at 4,725 feet (1,440 m)) and enters Montana.^[2]

Eastbound I-90 on the 1991 viaduct
at Wallace in 2007

History

Interstate 90 through Idaho was formerly U.S. Route 10,^[3] though some parts of I-90 were cut as new roadway.^[4][5] The small town of Wallace in the Silver Valley still prides itself on having what was the last stoplight on I-90. Its downtown has many historical buildings, which would have been wiped out by the original planned route of the freeway,^[6][7] so in 1976, city leaders had the downtown placed on the National Register of Historic Places.^[8][9][10] Alternatives discussed in 1963 included tunnels and twin levels.^[3][11]

As a result, the federal government was forced at great expense to reroute the freeway to the northern edge of downtown and elevate it. Work on that section was resumed in 1984,^[12] and it opened in September 1991.^[13] A bicycle path is routed beneath part of that segment. Before the move to the viaduct, I-90 went from a freeway at the western edge of Wallace, then turned to surface streets and followed the main arterial as U.S. Route 10 through town, which included the last stoplight on I-90 between Seattle and Boston.^[14] Upon reaching the eastern edge of the town it became a limited access divided highway once again.^[15]

The interstate also was routed along Lake Coeur d'Alene as a surface street before the Veterans Memorial Centennial Bridge was completed in the heights above the lake.

Exit list

County	Location	mi[1]	km	Exit[1]	Destinations	Notes
Kootenai	​	0.000	0.000		I‑90 west	Continuation into Washington
	Post Falls	1.160	1.867	1	Beck Road
		2.080	3.347	2	Pleasant View Road
		4.632	7.454	5	I-90 Business Loop east (Spokane Street) – City Center	Exit is just east of northernmost point on I-90
		5.450	8.771	6	I-90 Business Loop west (Seltice Way) – City Center	Westbound exit and eastbound entrance
		7.128	11.471	7	SH-41 north – Rathdrum, Spirit Lake
	Coeur d'Alene	11.290	18.169	11	I-90 Business Loop east (Northwest Boulevard) – City Center
		12.040	19.377	12	US-95 – Sandpoint, Moscow
		12.560	20.213	13	4th Street
		13.560	21.823	14	15th Street
		14.780	23.786	15	I-90 Business Loop west (Sherman Avenue) – City Center
	​	16.882	27.169	17	Mullan Trail Road
	​	22.063	35.507	22	SH-97 south – Harrison, St. Maries
	​	28.380	45.673	28	Fourth of July Pass Recreation Area
	​	34.028	54.763	34	SH-3 south – Rose Lake, St. Maries, Harrison
	​	39.024	62.803	39	Old Mission State Park
	​	40.096	64.528	40	Cataldo
Shoshone	​	43.016	69.228	43	Kingston
	​	45.261	72.841	45	Pinehurst, Smelterville
	​	47.687	76.745	48	Smelterville, Shoshone County Airport
	Kellogg	49.715	80.009	49	Bunker Avenue – Silver Mountain
		50.321	80.984	50	Hill Street	Eastbound exit and westbound entrance
		50.551	81.354	51	Division Street – Wardner	No westbound entrance
	​	54.186	87.204	54	Big Creek
	Osburn	57.036	91.791	57	I-90 Business Loop east – Osburn
	​	59.553	95.841	60	I-90 Business Loop west – Silverton, Osburn
	Wallace	60.990	98.154	61	I-90 Business Loop east – Wallace
		61.948	99.696	62	I-90 Business Loop west / SH-4 east – Wallace, Burke
	​	64.270	103.433	64	Golconda District
	​	65.352	105.174	65	Compressor District
	​	66.500	107.021	66	Gold Creek	Eastbound exit and entrance
	​	67.353	108.394	67	Morning District, West Mullan
	Mullan	68.100	109.596	68	I-90 Business Loop east – Mullan	Eastbound exit and westbound entrance
	​	68.908	110.897	69	I-90 Business Loop west – Mullan, East Mullan
	​	73.888	118.911		I‑90 east (Lookout Pass)	Continuation into Montana
1.000 mi = 1.609 km; 1.000 km = 0.621 mi       Incomplete access

Related routes

Route map: Bing / Google

• Interstate 90 Business (Coeur d'Alene, Idaho)
• Interstate 90 Business (Mullan, Idaho)
• Interstate 90 Business (Osburn, Idaho)
• Interstate 90 Business (Post Falls, Idaho)
• Interstate 90 Business (Wallace, Idaho)
• U.S. Route 10

References

1. "Milepoint Log Report" (PDF). Idaho Transportation Department. Retrieved July 11, 2015.
2. Idaho Official Highway Map (2007 ed.), Boise, Idaho: Idaho Department of Transportation, 2007
3. "Idaho eyes twin-level freeway". Spokane Daily Chronicle. Washington. Associated Press. December 18, 1963. p. 6.
4. "Idaho seeking funds to buy right of way for freeway route". Spokane Daily Chronicle. Washington. February 1, 1957. p. a3.
5. Leeright, Bob (July 31, 1971). "Displaced residents add to cost of highways". Spokane Daily Chronicle. Washington. Associated Press. p. 5.
6. "Plans for Interstate 90 explained to Wallace CC". Spokane Daily Chronicle. Washington. January 23, 1970. p. 3.
7. "Wallace Chamber seeks I-90 shift". Spokane Daily Chronicle. Washington. January 18, 1973. p. b3.
8. "Wallace freeway hearing ordered by federal judge". Spokesman-Review. Spokane, Washington. Associated Press. July 23, 1976. p. 13.
9. "I-90 study includes historic site survey". Spokane Daily Chronicle. Washington. January 10, 1980. p. 10.
10. Collin, Matthew (January 26, 1981). "Wallace freeway 12 years overdue". Spokesman-Review. Spokane, Washington. p. 6.
11. "Freeway alternatives reviewed for Wallace". Spokane Daily Chronicle. Washington. Associated Press. October 25, 1978. p. 5.
12. Bond, Dave (July 18, 1984). "Wallace bypass work to start". Spokesman-Review. Spokane, Washington. p. 1.
13. Idaho Transportation Department Archived September 26, 2006, at the Wayback Machine.
14. "He stalled Interstate 90 right in the middle of town". Eugene Register-Guard. Oregon. Associated Press. February 13, 1981. p. 15F.
15. "Lone stoplight on Interstate 90 to pass by after new bypass". The Bulletin. Bend, Oregon. Associated Press. September 8, 1991. p. A9.