.svg) Interstate 70 | ||||
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 I-70 highlighted in red | ||||
| Route information | ||||
| Maintained byUDOT | ||||
| Length | 231.673 mi[1] (372.842 km) | |||
| Existed | 1957[2]–present | |||
| NHS | Entire route | |||
| Major junctions | ||||
| West end |  I-15 nearCove Fort | |||
| Major intersections |
| |||
| East end |    I-70 /US 6 /US 50 atColorado state line | |||
| Location | ||||
| Country | United States | |||
| State | Utah | |||
| Counties | Millard,Sevier,Emery,Grand | |||
| Highway system | ||||
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Interstate 70 (I-70) is a mainline route of theInterstate Highway System in theUnited States connectingUtah andMaryland. The Utah section runs east–west for approximately 232 miles (373 km) across the central part of the state.Richfield is the largest Utah city served by the freeway, which does not serve or connect anyurban areas in the state. Thefreeway was built as part of a system of highways connectingLos Angeles and theNortheastern United States. I-70 was the second attempt to connect southern California to theeast coast of the United States via central Utah, the first being a failed attempt to construct atranscontinental railroad. Parts of that effort were reused in the laying out of the route of I-70.
Unlike most Interstate Highways, much of I-70 in Utah was not constructed parallel to or on top of an existingU.S. Route. Portions of I-70 were constructed in areas where previously there were no paved roads. Because it was built over an entirely new route, I-70 has many features that are unique in theInterstate Highway System. For example, the 110 miles (180 km) stretch betweenGreen River andSalina makes up the longest distance anywhere in the Interstate Highway System with no motorist services. This same piece is noted as the longest highway in the United States built over a completely new route since theAlaska Highway, and the longest section of Interstate Highway to open at a given time. The construction of the Utah portion of I-70 is listed as one of the engineering marvels of the Interstate Highway System.
The choice of the route had a significant impact on the character and culture of theSevier Valley. It has also been a motivating factor for environmentalists to create a newnational park along the path of the highway to protect scenic areas around the route. I-70 from Green River toGrand Junction, Colorado, is part of theDinosaur Diamond Prehistoric Highway, making I-70 one of the few Interstate Highways to be named aNational Scenic Byway. Attractions listed by theFederal Highway Administration (FHWA) for the Dinosaur Diamond Prehistoric Highway on or near I-70 include,Arches National Park,Canyonlands National Park,Cleveland-Lloyd Dinosaur Quarry,Goblin Valley State Park,Ruby Canyon, andWestwater Canyon. The designation also lists several side roads branching from I-70 that lead to dinosaur bones, footprints, and nativepetroglyphs.
I-70 begins at atrumpet interchange withI-15, nearCove Fort. It then proceeds east over thePahvant Range, cresting at Clear CreekSummit with an elevation of 7,180 feet (2,190 m).[3] The eastern descent from the Pahvant Range features bridges high aboveClear Creek and its side canyons. The longest of these bridges is the Fish Creek bridge at 1,180 feet (360 m) long.[4] The descent into Clear Creek features a brake check area andrunaway truck ramp to aidtruckers down the steep slope.[1] The freeway then skirts the edge ofFremont Indian State Park and Museum before enteringSevier Valley.
I-70 serves as the main thoroughfare of the valley, the only area traversed by the highway in Utah with more than a few hundred residents.Richfield is the largest city along I-70 in the state.[5] The highway enters the valley just north of Big Rock Candy Mountain, a mountain named fora song attributed toHarry McClintock.[6] The highway proceeds northeast along the western edge of the valley, passing to the west of the communities of the valley, includingJoseph,Monroe,Elsinore, and Richfield. As I-70 approaches Salina, it cuts across the valley passing to the south of the town. The highway avoids thedowntown areas of all of these cities.[7] The portion between Richfield and Salina is the busiest, with anannual average daily traffic (AADT) of 11,535 vehicles in 2006.[8] In the Sevier Valley, I-70 was built parallel toU.S. Route 89; both highways now run concurrently between exit 23 (US-89 south toMarysvale andPanguitch) and exit 56 in Salina.
At Salina,US-50 joins I-70, and the two highways runconcurrent for the rest of the way through Utah. After leaving exit 56 in Salina, I-70 departs on a 104-mile (167 km) course to the first Green River offramp, exit 160. Though there are a number of exits in between the two cities, it is the longest distance in theInterstate Highway System with no motorist services directly along the highway.[9] The route to Green River crosses two major geographic obstacles: theWasatch Plateau and theSan Rafael Swell.[10]
I-70 initially begins an ascent up the Wasatch Plateau via Salina Canyon. At lower elevations, this canyon separates the Wasatch Plateau to the north with the Sevier Plateau to the south. After climbing to a fork in the canyon, the highway turns south and crests the Wasatch Plateau at Emigrant Pass.[11] This pass is the highest point of any of Utah's Interstate Highways, although the elevation differs from source to source. NewerUtah Department of Transportation (UDOT) maps list the elevation of 7,886 feet (2,404 m), while older maps give the figure 7,923 feet (2,415 m).[7][12] This portion of I-70 is on protected lands as part ofFishlake National Forest.[1] The highway exits the Wasatch Plateau atFremont Junction, where I-70 meetsUtah State Route 10 (SR-10).
Between Fremont Junction and the junction ofSR-24 near Green River, I-70 crosses a geologic feature called theSan Rafael Swell. The construction of the highway through the swell is listed as one of the engineering marvels of the Interstate Highway System, with one engineer claiming this section as "one of the most significant highway construction feats of its time".[2] The construction of I-70 through the swell requiredboring through many solid rock canyons, cliffs, and mountains.[13] The swell is noted for its sheer canyons and rock formations and is home to a large amount of exposed dinosaur remains. This includes the largest known collection ofJurassic-period dinosaur remains at theCleveland-Lloyd Dinosaur Quarry at the north end of the swell.[14]
The highway ascends the western edge of the swell on a steady slope loosely following the north rim of Devils Canyon. At the top of thegrade is aview area with a view of Devils Canyon and an overlook of the landscape west of the swell.[10] It then crosses Eagle Canyon via a pair ofsteel arch bridges. The eastbound bridge is 489 feet (149 m) long,[15] and the westbound bridge is 523 feet (159 m) long.[16]
The highway then ascends Ghost Rock Summit, named for unusual rock formations nearby, and the highest point for I-70 inside the swell. At the summit is another view area overlooking theLittle Grand Canyon of the San Rafael River.[10] The Ghost Rocks themselves are at 7,405 feet (2,257 m), although the freeway is slightly lower.[10] I-70 meanders through a relatively flat portion of the swell until reaching Spotted Wolf Canyon, which provides the exit route to the swell. The eastern descent features one brake check area and tworunaway truck ramps to aid trucks down.[1] About halfway down is a view area of the canyon narrowing as it approaches the easternescarpment of the swell, theSan Rafael Reef. Just as the highway exits the swell nearGreen River, it passes to the north ofGoblin Valley State Park.
West of Green River,US-6 andUS-191 join I-70. Also at Green River, the freeway reaches the southern edge of theBook Cliffs, a mountain range which I-70 follows toGrand Junction, Colorado. This portion of I-70 is part of theDinosaur Diamond Prehistoric Highway, recognized as a scenic byway by both theNational Scenic Byways andUtah Scenic Byways programs.[17][18] Listed attractions along the byway in the Green River area includeCrystal Geyser,Capitol Reef National Park, andGreen River State Park.
From this point east, the freeway is routed across a flat area between the Book Cliffs and theColorado River, called Sagers Flat.[10] Along the way, it passes by the towns ofCrescent Junction,Thompson Springs, and theghost town ofCisco. Natural features visible from this portion includeArches National Park andCastle Valley. Other listed attractions along the byway near this section includeCanyonlands National Park and various areas withMorrison Formation, a layer of rock where dinosaur remains are common.[19] I-70, US-6, andUS-50 all enterColorado concurrently. Where I-70 follows the Book Cliffs, it was built parallel to or on top of US-6/US-50.[7]
The first route through this portion of Utah was theOld Spanish Trail, a trade route betweenSanta Fe, New Mexico, andLos Angeles, California. The trail was in common use before theMexican–American War in 1848.[20] Although the trail serves a different route than I-70, they were both intended to connect Southern California with points further east. I-70 generally parallels the route of the Old Spanish Trail west of Crescent Junction.I-15 south of the junction with I-70 also generally parallels the trail.[21]
The first attempt to build a modern trade route through the area is credited toWilliam Jackson Palmer, founder of theDenver and Rio Grande Western Railroad (D&RG). Palmer started a project in 1880 to make what had been a local railroad from Colorado into a transcontinental railroad empire. This would mean a second transcontinental railroad would be built across Utah. This would also place the D&RG in competition with thefirst transcontinental railroad, then operated by theUnion Pacific Railroad andCentral Pacific Railroad.[22]
Disagreements in the company led to two proposals. Both proposals called for extending the railroad west from Colorado as far as what is now Green River. West of Green River, a "northern route" would extend the railroad towardsOgden, Utah, there connecting with the establishedOverland Route. This proposal was eventually completed as theUtah Division, loosely following the route of modernUS-6 across eastern Utah. This line soon became the main line of the D&RG and remains one of the main transcontinental rail arteries of the US, now operated by the Union Pacific Railroad as theCentral Corridor.[23]
The second proposal was a "southern route" that would continue due west from Green River and head toward Los Angeles, similar to the route of modern I-70. This proposal would require extending the railroad farther west, to connect with what would become theLos Angeles and Salt Lake Railroad.[24]
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Due to disagreements in management and poor communication, construction began on both routes. It was soon obvious that the southern route was unfeasible given the remote area, technology available at the time, and the rough terrain of the San Rafael Swell. In 1883, the D&RG spent $217,470 (equivalent to $6.2 million in 2024[25]) on the project before declaring it a failure. One of the accounts in the bookUtah Ghost Rails states the railroad fired the leadsurveyor, even though the workers had graded a path past theSan Rafael Reef.[24] This route today is ajeep trail. According to a sign placed by theBureau of Land Management (BLM), had the southern route succeeded, it would have been the shortest transcontinental railroad in the US.[24]
Construction resumed in 1901 on a portion of the southern route, to build aspur line to service coal mines on theWasatch Plateau. The railroad branched from an existing line at Salina and traveled east up Salina Canyon. After the mines closed, the railroad bed was used to improveSR-10, between Salina and Fremont Junction. I-70 would later use the railroad bed for a path across the Wasatch Plateau.[24]
By the time theInterstate Highway System was in the planning stages, no paved road had yet entered theSan Rafael Swell.[26] The established highway through the area was US-6/US-50 which, like the railroad, entered Utah from Colorado and turned north around the swell.[27]
As first proposed in 1956, the western terminus of I-70 wasDenver, Colorado.[2] Officials from Colorado pressured the federal government to extend the plans for I-70 further west. After several discussions with Utah officials, Utah supported an extension that would follow US-6/US-50 (now US-6), to connect with I-15 atSpanish Fork. This proposal would connect theSalt Lake City area with Denver. While accepting the Colorado/Utah proposal, federal planners also decided to show a modified proposal, with the terminus of I-70 atCove Fort, to planners at theDepartment of the Army. The planners opposed the extension to Salt Lake but felt the modified proposal would benefit the US Army by providing a better connection to southern California. The new route would shorten the distance between Los Angeles and Denver by about 200 miles (320 km). The route to Cove Fort was approved on October 18, 1957. A general announcement was made, with no prior notice given to Utah officials of the modification. The commissioner of theBureau of Public Roads later admitted that the lack of notice was intentional, fearing infighting if the bureau did not announce a final decision.[2]
A state historian stated the news hit Utah "like a bombshell". Except for the officials in Utah that represented the area, most opposed a freeway that would serve no populated areas in the state. The route was mocked as a public relations blunder and a "road to nowhere".[2][9] Utah officials attempted to revert plans to their preferred alternative but later resigned to construct I-70 on the federally selected route. GovernorGeorge Dewey Clyde concluded, "Utah had no choice but to accept the Cove Fort routing, or have none at all."[2] Even attempts to route the freeway slightly north, to serve more cities inEmery County, were blocked. Federal planners insisted the freeway pass Green River on a southwest course and not turn north.[2] Even today, there is no direct Interstate link between Salt Lake City and Denver. Motorists must choose between the two lane routes (US-6 orUS-40) or detour onI-80 throughWyoming.[28]
With the plans for I-70 extended, a transcontinental route would again be attempted across the San Rafael Swell. The area west of Green River was so remote that survey crews followed wild horses with jeeps to survey parts of the route. According to a story told at the highway's dedication by an engineer who surveyed the highway, his group was approached by a sheep rancher and asked what they were doing. The rancher fell over laughing when he was told they were building a freeway.[29]
The survey crew did not use the route of the railroad past theSan Rafael Reef. However, they did use the route of the railroad across the Wasatch Plateau. The construction crews destroyed two of four tunnels when the bed was widened for the freeway. The two remaining tunnels are visible just south of the freeway and are used by afrontage road.[24]
Some noncontiguous portions of I-70 over the Pavant Range and Wasatch Plateau were temporarily signed as SR-4.[3] The portion over the San Rafael Swell opened to traffic in 1970, finally making the Utah portion of I-70 a drivable route.[2]
I-70 was dedicated on December 5, 1970, at the Ghost Rocks view area inside the swell, even though it would take another 20 years to fully complete the freeway.[2] At the ceremony, the mayors of cities recently made neighbors, includingGrand Junction, Colorado, introduced themselves. Then-GovernorCal Rampton noted that I-70 was the longest road the US had built over a completely new route since theAlaska Highway, duringWorld War II. It was also noted this was the longest piece of the Interstate Highway System to open at a given time.[2]
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Initially only two lanes, now the eastbound lanes, through the swell were constructed. The official highway map for Utah noted the new freeway but qualified its existence with the words "two lanes open".[3]
The Utah portion of I-70 was not completed to Interstate Highway standards until October 1990, when the second Eagle Canyon bridge was dedicated. The new bridge carried westbound traffic while the 1970 bridge switched to eastbound only traffic.[30] A second dedication ceremony was held at new bridge to declare the Utah portion of I-70 complete. Archie Hamilton, one of three engineers who worked forUDOT long enough to see I-70 progress from conception to completion, said the most memorable moment was seeing theexcavation at Spotted Wolf Canyon. He said before construction began, he could stand in one spot and touch both sides of the canyon. To carve the first eight miles (13 km) through the canyon required excavating 3,500,000 cubic yards (2,700,000 m3) of rock. In 1990, it was estimated construction cost for the San Rafael Swell portion was $388 million (equivalent to $821 million in 2024[25]); $105.5 million in 1970 (equivalent to $656 million in 2024[25]) to build the first two lanes and $78 million in 1990 (equivalent to $165 million in 2024[25]) to construct the rest.[29][31] At the 1970 dedication, it was noted the cost of land acquisition helped to offset the cost of the massive excavation. UDOT acquired the right of way to build the majority of I-70 from the BLM at the lowest cost per mile of any highway in Utah.[2]
In 2002, theSalt Lake Tribune interviewed the mayor of Richfield about the change I-70 brought to theSevier Valley. Previously, these were isolated farming communities, whose residents felt they were unaccustomed to the crime and other effects that a transcontinental highway can bring. Residents of Richfield soon started to call I-70 "Cocaine Lane". The mayor stated that I-70 is a mixed blessing. He stated the highway is a boon to the hospitality industry and has made Richfield more accessible to other cities. However, the new road brought types of crime previously unknown to the city. The mayor lamented that after the completion of I-70, many residents started locking their doors for the first time. The interview resulted from an event that served as a "wake-up call", that rural Utah is "not isolated from crime". Panic ensued after the public witnessedUtah Highway Patrol troopers carrying away a suspect in handcuffs while removing plastic bags and coolers full of body parts from the trunk of his car. The event caused a frenzy of people checking on their neighbors, fearing the murder victims were local residents.[32] In 2007, there were 11 violent crimes in Sevier County,[33] a county of 19,386 residents.[34]
Green River is the largest and only incorporated city directly served by I-70 in eastern Utah.[5][10] Unlike the communities of the Sevier Valley, Green River was founded as a stopover for travelers along transcontinental arteries. The area was first used as a stopover for travelers navigating the Green River. Later, the town was formed to serve travelers along the Old Spanish Trail and stagecoach mail routes. Green River was an established stopover by the time the railroad and later highways were built through the area.[35]
Before the construction of I-70, the San Rafael Swell was relatively inaccessible and not well known or explored. There were, however, a few efforts to protect the swell as early as 1935.[26] Since the construction of the freeway, the number of visitors to the swell has increased significantly, as the swell can now be accessed by automobile.[26] As such, several groups are increasing efforts for protected status of the area, vianational park,national monument, orwilderness designation.
A major push occurred in 2002 when officials fromEmery County, joined by Utah governorMike Leavitt, petitioned PresidentGeorge W. Bush to use the authority of theAntiquities Act and create a San Rafael Swell National Monument.[36] This effort lost momentum after the governor promised to honor the wishes of Emery County residents via a nonbindingreferendum, which did not pass.[37] Common reasons given by residents for opposing the designation included fear of the federal government restricting access and a repetition of events that occurred with theGrand Staircase–Escalante National Monument. This monument was established in 1996 by PresidentBill Clinton. In that case, the monument was proposed at the federal level in secret. Boundaries were drawn without the consent or even knowledge of local residents. This incited anger and triggered a backlash in rural Utah.[38]
Most of the swell is administered by theBLM and is not given special consideration.[26] A small portion on the eastern edge is protected asGoblin Valley State Park, administered by theUtah Division of Parks and Recreation. In 2019, after lobbying by theSouthern Utah Wilderness Alliance, congress directed the BLM to study 17 specific areas of Southern Utah for designation as a wilderness areas, including several in the San Rafael Swell. In the same act, Congress directed the BLM to create a San Rafael Swell Recreational Area.[39][40]
Before the formation of I-70, there was a road over the Pavant Range numberedSR-13 that was similar to the route of I-70. The highway, which largely still exists as a two-lane road betweenSR-161 (formerUS-91) at Cove Fort andUS-89 at Sevier, had been taken over by the state on August 2, 1912,[41] and assigned the label by the early 1920s as part of Utah's initial highway numbering.[42] In the Wasatch Plateau, the base for I-70 was derived from a portion ofSR-10. Both of these were transferred to SR-4, which was the state legislative designation for all of I-70 in Utah, in 1962.[43] US-50 was changed to overlap with I-70 through most of Utah in 1976, with US-6 remaining on its former route.[44]In 1977, Utah renumbered its state routes so that the legislative and signed numbers would match. With this change, the state designation for I-70 is now SR-70.[43]
| County | Location | mi[1] | km | Exit | Destinations | Notes |
|---|---|---|---|---|---|---|
| Millard | | 0.000 | 0.000 | — | I-15 –Las Vegas,Salt Lake City | Western terminus; I-15 exit 132;trumpet interchange |
| | 1.346 | 2.166 | 1 | Historic Cove Fort (SR-161) | ||
| Sevier | | 7.835 | 12.609 | 7 | Clear Creek Canyon Road | |
| | 17.159 | 27.615 | 17 | Fremont Indian State Park | ||
| | 23.188 | 37.317 | 23 |   US 89 south –Panguitch,Kanab | West end of US-89 overlap | |
| Joseph | 25.763 | 41.462 | 25 |   SR-118 north –Joseph,Monroe | ||
| Elsinore | 31.676 | 50.978 | 31 | Elsinore,Monroe (SR-258) | ||
| Richfield | 37.124 | 59.745 | 37 |    I-70 BL east /SR-120 –Richfield | ||
| 40.258 | 64.789 | 40 |  I-70 BL west /SR-120 –Richfield | |||
| | 48.920 | 78.729 | 48 |   ToSR-24 (SR-259) –Sigurd,Aurora | ||
| Salina | 56.705 | 91.258 | 56 |   I-70 BS /US 89 north /US 50 west –Salina | East end of US-89 overlap; west end of US-50 overlap | |
| | 63.193 | 101.699 | 63 | Gooseberry Road | ||
| | 73.924 | 118.969 | 73 | Salina Creek | Formerly signed as "Ranch Exit" | |
| | 86.773 | 139.648 | 86 | Ivie Creek rest area | Access viaSR-76 | |
| | 91.011 | 146.468 | 91 |   SR-10 north /SR-72 south –Price,Loa | ||
| Emery | | 99.488 | 160.110 | 99 | Millers Canyon | Formerly signed as "Ranch Exit" |
| | 104.620 | 168.370 | Salt Wash view area | |||
| | 108.011 | 173.827 | 108 | Lone Tree | Formerly signed as "Ranch Exit" | |
| | 115.634 | 186.095 | Devil's Canyon view area (eastbound) | |||
| | 116.513 | 187.509 | 116 | Moore | Eagle Canyon view area also signed westbound | |
| | 122.566 | 197.251 | Ghost Rocks view area | |||
| | 131.507 | 211.640 | 131 | Temple Mountain Road | Formerly signed as "Ranch Exit" | |
| | 142.585 | 229.468 | Spotted Wolf Canyon view area | |||
| | 146.337 | 235.507 | San Rafael Reef view area (westbound) | |||
| | 149.198 | 240.111 | 149 | SR-24 west –Hanksville | ||
| | 157.924 | 254.154 | 157 |  US 6 west /US 191 north –Price,Salt Lake City | West end of US-6/191 overlap | |
| | 160.403 | 258.144 | 160 |   I-70 BL /SR-19 east –Green River | I-70 Bus. not signed westbound | |
| Grand | | 164.547 | 264.813 | 164 | I-70 BL /SR-19 west –Green River | I-70 Bus. not signed eastbound |
| | 175.585 | 282.577 | 175 | Floy | ||
| Crescent Junction | 182.153 | 293.147 | 182 | US 191 south –Crescent Junction,Moab | East end of US-191 overlap; former US-160 east | |
| | 187.413 | 301.612 | 187 |  SR-94 –Thompson Springs | ||
| | 189.876 | 305.576 | Rest area / Visitors Center (westbound) | |||
| | 193.469 | 311.358 | 193 | Yellowcat | ||
| | 204.738 | 329.494 | 204 |  SR-128 south –Cisco | ||
| | 214.367 | 344.990 | 214 | Danish Flat | ||
| | 221.885 | 357.089 | 221 | Sulphur | ||
| | 227.086 | 365.459 | 227 | Westwater | ||
| | 228.352 | 367.497 | Harley Dome view area (westbound) | |||
| | 231.673 | 372.842 |  I-70 east /US 6 east /US 50 east –Grand Junction,Denver | Continuation intoColorado | ||
1.000 mi = 1.609 km; 1.000 km = 0.621 mi
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 Interstate 70 | ||
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