History of Interstate 70 in Utah

By | October 14, 2022

Before I-70 was built, US 6 and US 50 existed. The original connection was from Salt Lake City in the US 6 corridor through the Spanish Fork Canyon. US 50 originally followed this corridor as well. US 89 also existed between Sevier and Salina, which forms a north-south route through Utah.

Much of the route where I-70 was built does not follow historic road connections. Construction of I-70 has been completed through one of the most remote parts of the United States, specifically the 170-kilometer stretch between Salina and Green River, where the highway has been built through completely undeveloped desert land. The construction of this part was complex due to the total lack of infrastructure in this area.

  • WATCHTUTORIALS.ORG: Features why Utah has the nickname as Beehive State and its economy, history and geography.

The first proposal for the construction of Interstate Highways beginning in 1956 intended that I-70 be no further west than Denver because of the costly nature of building a highway through such mountainous terrain. Later plans envisaged an I-70 into Utah, following the US 6/50 corridor to Spanish Fork. I-70 would mainly become a connection between Salt Lake City and Denver. However, the federal government preferred to build a route that would connect a lot more south with I-15, significantly shortening the distance to the southwestern United States. This route of I-70 shortened the distance between Los Angeles and Denver by more than 300 kilometers from the plan toward Salt Lake City.

However, the state of Utah was not happy with this plan, which would take long stretches through uninhabited areas, they called it a ‘road to nowhere’. Working out the construction plans between Salina and Green River was problematic. The terrain was so rugged that it was only possible to map the route on horseback. Portions of I-70 followed the remnants of a part-built 19th century transcontinental railroad. At the time, the construction of this railway was abandoned due to the impossible terrain. However, the construction of I-70 would succeed.

  • acronymmonster.com: Provides state overview of Utah and its alternative name as The Beehive State

Construction of I-70

The first section of I-70 to open was a short stretch west of Crescent Junction, which was commissioned circa 1960. Presumably that was a simple doubling of US 6/50 at the time, but it was indicated on maps as I-70 from the start. In 1965, the second section opened, the interchange with I-15 at Cove Fort. The third section opened circa 1969, a stretch through a shallow canyon east of Salina.

The main road opening was the section through the San Rafael Swell, a 111-kilometer stretch between Fremont Junction and Green River that opened on December 5, 1970. This was the longest roadway in the history of the United States, and the construction of I-70 was considered the only post-war road construction through such an undeveloped part of the United States, comparable to the construction of the Alaska Highway in Canada during the WWII. Land acquisition costs were the lowest of all roads in the United States because the land could be purchased from the Bureau of Land Management for a very small price.

Portions of I-70 between Salina and Green River were originally built with a single carriageway. At the time, there was no proven traffic demand in this corridor because there were no previous roads. Traffic would mainly consist of long-distance traffic and traffic volumes were very low at the time. The highway was doubled in phases throughout the 1970s and 1980s, and was completed in 1990 with the opening of the second bridge over Eagle Canyon.

In the mid-1970s, I-70 was already significantly completed in the eastern part of the state, with only a missing link near Green River. It is striking that the section that leads through the most densely populated part of the route was built last, namely the section from Sevier to Salina, which leads through an agricultural valley with more places.

In 1976, US 50 was extensively rerouted through central Utah. It originally followed US 6 via Spanish Fork, but was moved south via Salina to use the new route offered by I-70. However, this resulted in a fairly long double numbering from Salina to the border with Colorado.

After 1975, construction of I-70 was halted for some time. In the early 1980s, circa 1984, the Green River bypass was opened, completing the eastern portion of I-70. Construction continued on the western portion of I-70 in the 1980s, first through the canyon between Cove Fort and Sevier, which also opened circa 1984. Construction progressed through the Sevier Valley throughout the 1980s and was completed by 1989, with the final section opening between Richfield and Sigurd. The construction of I-70 gave new impetus to the Sevier Valley, an area that until then had a shrinking population, but started to see substantial growth from the 1970s. The village of Richfield grew into the main regional center of central Utah.

Opening history

from nasty length date
Exit 175 Old Hwy 6 & 50 Exit 182 Crescent Junction 11 km 00-00-1960
Exit 0 I-15 Exit 7 Clear Creek Canyon Road 11 km 00-00-1965
Exit 63 Gooseberry Road Exit 73 Convulsion Road 16 km 00-00-1969
Exit 91 Fremont Junction Exit 160 Green River (west) 111 km 05-12-1970
Exit 204 State Highway 128 Exit 227 Old US Hwy 6 & 50 37 km 00-00-1971
Exit 193 BLM 163 Exit 204 State Highway 128 18 km 00-00-1974
Exit 227 Old US Hwy 6 & 50 Exit 232 Colorado state line 8 km 00-00-1974
Exit 73 Convulsion Road Exit 91 Fremont Junction 29 km 00-00-1975
Exit 182 Crescent Junction Exit 193 BLM 163 18 km 00-00-1975
Exit 56 Salina Exit 63 Gooseberry Road 11 km 00-00-1976
Exit 164 Green River (east) Exit 175 Old Hwy 6 & 50 18 km 00-00-1982?
Exit 160 Green River (west) Exit 164 Green River (east) 6 km 00-00-1984?
Exit 7 Clear Creek Canyon Road Exit 17 Clear Creek Canyon Road (east) 16 km 00-00-1984?
Exit 17 Clear Creek Canyon Road (east) Exit 31 Elsinore 23 km 00-00-1987?
Exit 48 Sigurd Exit 56 Salina 13 km 00-00-1987?
Exit 31 Elsinore Exit 37 Richfield South 10 km 00-00-1988
Exit 37 Richfield South Exit 48 Sigurd 18 km 00-00-1989

History of Interstate 70 in Utah