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, Salt Lake City, Idaho Falls, 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 93 (US 93) is a major north–south 1,359-mile (2,187 km) U.S. Numbered Highway in the western United States, that connects U.S. Route 60 (US 60) in Wickenburg, Arizona, with British Columbia Highway 93 at the Canadian border. The highway passes through Kingman, Arizona; Las Vegas, Nevada; Twin Falls, Idaho; and Missoula, Montana.
Interstate 184 (I-184) is a short auxiliary Interstate Highway in Boise, Idaho, United States. The only auxiliary Interstate in Idaho, it is a spur route of I-84 that connects the freeway to Downtown Boise, terminating at US Highway 20 (US 20) and US 26 on the west side of the Boise River.
U.S. Route 91 or U.S. Highway 91 is a 172.7-mile-long (277.9 km) north–south United States highway running from Brigham City, Utah, to Idaho Falls, Idaho, in the U.S. states of Idaho and Utah. Despite the "1" as the last digit in the number, US 91 is no longer a cross-country artery, as it has mostly been replaced by Interstate 15. The highway currently serves to connect the communities of the Cache Valley to I-15 and beyond. Prior to the mid-1970s, US 91 was an international commerce route from Long Beach, California, to the Canada–US border north of Sweetgrass, Montana. US 91 was routed on the main streets of most of the communities it served, including Las Vegas Boulevard in Las Vegas and State Street in Salt Lake City. From Los Angeles to Salt Lake, the route was built along the corridor of the Arrowhead Trail. A portion of the highway's former route in California is currently State Route 91.
U.S. Route 191 is a north–south highway in the Western United States and a spur of parent route U.S. Route 91 that has two segments. The southern segment runs for 1,102 miles (1,773 km) from Douglas, Arizona on the Mexican border to the southern part of Yellowstone National Park. The northern segment runs for 442 miles (711 km) from the northern part of Yellowstone National Park to Loring, Montana, at the Canada–US border. Unnumbered roads within Yellowstone National Park connect the two segments. The highway passes through the states of Arizona, Utah, Wyoming, and Montana.
Interstate 84 (I-84) is an Interstate Highway in the northwestern United States. The highway runs almost 770 miles from Portland, Oregon, to a junction with I-80 near Echo, Utah. The highway serves and connects Portland, Boise, and Ogden, Utah. With connections to other highways, I-84 connects these cities to points east and also serves as part of a corridor between Seattle and Salt Lake City. The sections running through Oregon and Idaho are also known as the Vietnam Veterans Memorial Highway.
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.
Interstate 84 (I-84) is a part of the Interstate Highway System that links Portland, Oregon, to I-80 near Echo, Utah. The 117.38-mile-long (188.90 km) segment in the US 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 Ogden-Hinckley Airport. Turing east along the Davis County border, I-84 intersects US 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.
Interstate 84 (I-84) in the U.S. state of Oregon is a major Interstate Highway that traverses the state from west to east. It is concurrent with U.S. Route 30 (US 30) for most of its length and runs 376 miles (605 km) from an interchange with I-5 in Portland to the Idaho state line near Ontario. The highway roughly follows the Columbia River and historic Oregon Trail in northeastern Oregon, and is designated as part of Columbia River Highway No. 2 and all of the Old Oregon Trail Highway No. 6; the entire length is also designated as the Vietnam Veterans Memorial Highway. I-84 intersects several of the state's main north–south roads, including US 97, US 197, I-82, and US 395.
U.S. Route 89 in the U.S. state of Utah is a north-south United States Highway spanning more than 502 miles (807.891 km) through the central part of the state, making it the longest road in Utah. Between Provo and Brigham City, US-89 serves as a local road, paralleling Interstate 15, but the portions from Arizona north to Provo and Brigham City northeast to Wyoming serve separate corridors. The former provides access to several national parks and Arizona, and the latter connects I-15 with Logan, the state's only Metropolitan Statistical Area not on the Interstate.
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.
U.S. Route 30 (US 30) runs northwest–southeast across the southern half of lower Idaho for 455.481 miles (733.026 km). US 30 enters the state from Oregon across the Snake River in Fruitland and exits into Wyoming east of Dingle. US 30 runs through the large population centers of Boise, Twin Falls, and Pocatello, as well as a plethora of smaller communities from Fruitland to Montpelier. The Thousand Springs Scenic Byway is a picturesque section of US 30 in southern Idaho between the towns of Bliss and Buhl, dipping down into the Hagerman Valley and a canyon of the Snake River.
U.S. Highway 26 (US-26) runs east–west across south central Idaho for 402.5 miles (647.8 km). US-26 enters the state from Oregon across the Snake River east of Nyssa, Oregon, concurrent with US-20 and exits into Wyoming northwest of Alpine. US-26 runs through the large population centers of Boise and Idaho Falls, as well as the smaller communities of Parma, Notus, Garden City, Shoshone, Richfield, Carey, Arco, Blackfoot, Swan Valley, and Irwin.
State Highway 19 (SH-19) is a state highway in Idaho from the Oregon state line to Interstate 84 (I-84) and U.S. Route 30 (US 30) in Caldwell. SH-19 is signed as an east–west highway.
Transportation in Montana comprises many different forms of travel. Montana shares a long border with Canada, hence international crossings are prevalent in the northern section of the state; there are 13 road crossings and one rail crossing.
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.
