Interstate 70 in Utah

Interstate 70
I-70 highlighted in red
Route information
Maintained by UDOT
Length	231.673 mi[1] (372.842 km)
Existed	1957[2]–present
NHS	Entire route
Major junctions
West end	I-15 near Cove Fort
Major intersections	US 89 near Joseph US 50 / US 89 in Salina US 6 / US 191 near Green River US 191 at Crescent Junction
East end	I-70 / US 6 / US 50 at Colorado state line
Location
Country	United States
State	Utah
Counties	Millard, Sevier, Emery, Grand
Highway system
Interstate Highway System Main Auxiliary Suffixed Business Future Utah State Highway System Interstate US State Minor Scenic
← SR-68 → SR-71

Interstate 70 (I-70) is a mainline route of the Interstate Highway System in the United States connecting Utah and Maryland. 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 any urban areas in the state. The freeway was built as part of a system of highways connecting Los Angeles and the Northeastern United States. I-70 was the second attempt to connect southern California to the east coast of the United States via central Utah, the first being a failed attempt to construct a transcontinental 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 existing U.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 the Interstate Highway System. For example, the 110 miles (180 km) between Green River and Salina 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 the Alaska Highway, and the longest piece 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 the Sevier Valley. It has also been a motivating factor for environmentalists to create a new national park along the path of the highway to protect scenic areas around the route. I-70 from Green River to Grand Junction, Colorado, is part of the Dinosaur Diamond Prehistoric Highway, making I-70 one of the few Interstate Highways to be named a National Scenic Byway. Attractions listed by the Federal 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, and Westwater Canyon. The designation lists several side roads branching from I-70 that lead to dinosaur bones or footprints.