| Interstate Highways of the Idaho State Highway System | |
|---|---|
   Typical Interstate highway markers | |
| System information | |
| Maintained by ITD | |
| Highway names | |
| Interstates | Interstate n (I-n) |
| US Highways | U.S. Highway n (US-n) |
| State | Idaho State Highway n (SH-n) |
| System links | |
| |
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.
| Number | Length (mi) [1] | 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 | 1957 | current | ||
 I-15W | 62.850 | 101.147 | I-84 / US 30 near Declo | I-15 in Chubbuck | 1957 | 1978 | Became I-86 | |
 I-80N | 275.650 | 443.616 | I-84 near Fruitland | I-84 near Black Pine | 1957 | 1980 | Became I-84 | |
 I-84 | 275.650 | 443.616 | I-84 near Fruitland | I-84 near Black Pine | 1980 | current | Designated as I-80N until 1980 | |
 I-86 | 62.850 | 101.147 | I-84 / US 30 near Declo | I-15 in Chubbuck | 1978 | current | Designated as I-15W until 1978 | |
 I-90 | 73.888 | 118.911 | I-90 in State Line | I-90 at Lookout Pass | 1957 | current | ||
 I-180N | 3.620 | 5.826 | I-84 / US 30 in Boise | US 20 / US 26 in Boise | 1970 | 1979 | Became I-184 | |
 I-184 | 3.620 | 5.826 | I-84 / US 30 in Boise | US 20 / US 26 in Boise | 1979 | current | Designated as I-180N until 1979, completed in 1990 | |
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| Number | Length (mi) [1] | 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 | 1972 | 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 | — | — | ||
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Interstate 15 (I-15) is a major Interstate Highway in the western United States, running through Southern California and the Intermountain West. I-15 begins near the Mexican border in San Diego County and stretches north to Alberta, Canada, passing through the states of California, Nevada, Arizona, Utah, Idaho, and Montana. The Interstate serves the cities of San Diego, San Bernardino, Las Vegas, St. George, Provo, Salt Lake City, Ogden, Pocatello, Idaho Falls, Butte, Helena, and Great Falls. It also passes close to the urban areas of Los Angeles, Orange, and Riverside counties, California. The stretches of I-15 in Idaho, Utah, and Arizona have been designated as the "Veterans Memorial Highway". The southern end is at a junction with I-8 and State Route 15 (SR 15) in San Diego, and the northern end is at a connection with Alberta Highway 4 at the Sweetgrass–Coutts Border Crossing.
U.S. Route 30 or U.S. Highway 30 (US 30) is an east–west main route in the system of the United States Numbered Highways, with the highway traveling across the northern tier of the country. With a length of 3,073 miles (4,946 km), it is the third longest U.S. highway, after US 20 and US 6. The western end of the highway is at US 101 in Astoria, Oregon; the eastern end is at Virginia Avenue, Absecon Boulevard, and Adriatic Avenue in Atlantic City, New Jersey. The "0" as the last digit in the number indicates that it is a coast-to-coast route and a major east-west route. Despite long stretches of parallel and concurrent Interstate Highways, it has not been decommissioned unlike other long haul routes such as US 66.
U.S. Route 93 (US 93) is a major north–south United States highway in the western United States. The southern terminus is at US 60 in Wickenburg, Arizona. The northern terminus is at the Canada–US border north of Eureka in Lincoln County, Montana, where the roadway continues into Roosville, British Columbia, as Highway 93. Major cities that US 93 travels through include: Kingman, Arizona; Las Vegas, Nevada; Twin Falls, Idaho; and Missoula, Montana.
Interstate 184 (I-184) is a short Auxiliary Interstate Highway in Boise, Idaho. It is a spur route of I-84 that connects the freeway to Downtown Boise, terminating at U.S. Route 20 (US 20) and U.S. Route 26 (US 26).
Interstate 86 (I-86) is an east–west intrastate Interstate Highway located entirely within the state of Idaho. It runs approximately 63 miles (101 km) from an intersection with I-84 east of Declo in rural Cassia County, to an intersection with I-15 in Chubbuck, just north of Pocatello. The highway is part of the main route from Boise and Twin Falls to Idaho Falls and the upper Snake River region.
State Highway 103 in the U.S. state of Colorado runs from Interstate 70 (I-70), U.S. Route 6 and US 40 at Idaho Springs to county roads 151 and 103 at Squaw Pass. The 13 miles (19 km) from Idaho Springs to SH 5 forms about half of the Mount Evans Scenic Byway.
Interstate 84 (I-84) is a part of the Interstate Highway System that links Portland, Oregon to I-80 near Echo, Utah. The 119.77-mile-long (192.75 km) segment in the U.S. state of Utah is the shortest of any of the three states the western I-84 passes through, and contains the eastern terminus of the highway. I-84 enters Box Elder County near Snowville before becoming concurrent with I-15 in Tremonton. The concurrent highways travel south through Brigham City and Ogden and separate near the Ogden-Hinckley Airport. Turing east along the Davis County border, I-84 intersects U.S. Route 89 (US-89) and enters Weber Canyon as well as Morgan County. While in Morgan County, I-84 passes the Devil's Gate-Weber Hydroelectric Power Plant and Devil's Slide rock formation. Past Morgan, the highway crosses into Summit County, past the Thousand Mile Tree before reaching its eastern terminus at I-80 near Echo.
Interstate 84 (I-84) in the U.S. state of Idaho is a major Interstate Highway that traverses the state from the Oregon state line in the northwest to Utah state line in the southeast. It primarily follows the Snake River across a plain that includes the cities of Boise, Mountain Home, and Twin Falls. The highway is one of the busiest in Idaho and is designated as the Vietnam Veterans Memorial Highway.
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.
State Highway 3 (SH-3) is a state highway in northern Idaho, connecting U.S. Route 12 near Spalding, east of Lewiston, with Interstate 90 near Rose Lake, east of Coeur d'Alene. It is 117.68 miles (189.4 km) in length and runs north–south, east of and generally parallel to Idaho's primary north–south highway, U.S. Route 95.
U.S. Route 95 (US 95) is a United States Numbered Highway, stretching from the Mexican border in San Luis, Arizona to the Canadian border near Eastport, Idaho. The California portion of US 95 traverses through the far eastern edges of both Riverside and San Bernardino counties. US 95 serves Blythe and Needles and junctions with SR 62 at Vidal Junction.
State Highway 24 (SH-24) is a 67.5 mi (108.6 km) long state highway in Idaho that runs east west from Shoshone, Idaho on the far west to Minidoka and Acequia on the far east.
In the U.S. state of Nevada, U.S. Route 93 is a major United States Numbered Highway traversing the eastern edge of the state. The highway connects the Las Vegas area to the Great Basin National Park, and provides further connections to Ely and Wells. US 93 also provides the majority of the most direct connection from the major metropolitan areas of Las Vegas and Phoenix to the Boise, Idaho metropolitan area.
State Highway 39 (SH-39) is a 52.924-mile-long (85.173 km) state highway located in Power and Bingham counties in Idaho. SH-39 runs from its southern terminus at Interstate 86 (I-86) in American Falls to its northern terminus at U.S. Route 26 (US-26) in Blackfoot. Between the two cities, it passes through the city of Aberdeen and the communities of Springfield and Pingree.
Several special routes of U.S. Route 30 exist. In order from west to east they are as follows.
State Highway 22 (SH-22) is a 43.936-mile-long (70.708 km) state highway in Idaho from SH-33 to Interstate 15 (I-15) in Dubois.
State Highway 36 (SH-36) is a 73.313-mile-long (117.986 km) east-west state highway located in the southeast part of the U.S. state of Idaho. SH-36 runs from Interstate 15 (I-15) near Malad City to U.S. Route 89 (US-89) near Montpelier. The highway is maintained by the Idaho Transportation Department.
State Highway 81 (SH-81) is a state highway in Cassia County, Idaho. The highway runs for 33.978 miles (54.682 km) from SH-77 in Malta to U.S. Route 30 (US-30) in Burley. It also has a short spur route connecting the highway to Interstate 84 (I-84) at the Yale Interchange.
Media related to Interstate Highways in Idaho at Wikimedia Commons