Interstate 90 in Idaho

Interstate 90
Purple Heart Trail
I-90 highlighted in red
Route information
Maintained by ITD
Length	73.888 mi[1] (118.911 km)
Existed	1957–present
History	Completed in 1991
NHS	Entire route
Major junctions
West end	I-90 at the Washington state line
Major intersections	SH-41 in Post Falls US 95 in Coeur d'Alene SH-97 near Coeur d'Alene SH-3 near Cataldo I-90 BL / SH-4 in Wallace
East end	I-90 at the Montana state line
Location
Country	United States
State	Idaho
Counties	Kootenai, Shoshone
Highway system
Interstate Highway System Main Auxiliary Suffixed Business Future Idaho State Highway System Interstate US State
← US 89 → US 91

Interstate 90 (I-90) is a transcontinental Interstate Highway that runs east–west across the northern United States. Within the state of Idaho, the freeway travels for 74 miles (119 km) from the Washington border near Spokane to Coeur d'Alene and the panhandle region at the north end of the state. After traveling through the Silver Valley along the Coeur d'Alene River in the Bitterroot Range, I-90 crosses into Montana at Lookout Pass.

I-90 was created by the federal government in 1957, following the general route of U.S. Route 10 (US 10) and the mid-19th century Mullan Road constructed by the U.S. Army. The freeway was constructed in stages between 1960 and 1992.