Interstate 70 in Colorado

Interstate 70
I-70 highlighted in red
Route information
Maintained by CDOT
Length	449.589 mi[1] (723.543 km)
History	Designated in 1956 Completed in 1992
NHS	Entire route
Restrictions	No hazardous goods allowed in the Eisenhower Tunnel
Major junctions
West end	I-70 / US 6 / US 50 at Utah state line
Major intersections	US 50 in Grand Junction US 24 near Vail US 40 near Empire I-76 in Arvada I-25 / US 87 in Denver I-270 / US 36 in Denver I-225 in Aurora US 40 / US 287 in Aurora E-470 in Aurora US 24 in Limon
East end	I-70 / US-24 at Kansas state line
Location
Country	United States
State	Colorado
Counties	Mesa, Garfield, Eagle, Summit, Clear Creek, Jefferson, Denver, Adams, Arapahoe, Elbert, Lincoln, Kit Carson
Highway system
Interstate Highway System Main Auxiliary Suffixed Business Future Colorado State Highway System Interstate US State Scenic
← SH 69 → SH 71

Interstate 70 (I-70) is a transcontinental Interstate Highway in the United States, stretching from Cove Fort, Utah, to Baltimore, Maryland. In Colorado, the highway traverses an east–west route across the center of the state. In western Colorado, the highway connects the metropolitan areas of Grand Junction and Denver via a route through the Rocky Mountains. In eastern Colorado, the highway crosses the Great Plains, connecting Denver with metropolitan areas in Kansas and Missouri. Bicycles and other non-motorized vehicles, normally prohibited on Interstate Highways, are allowed on those stretches of I-70 in the Rockies where no other through route exists.

The United States Department of Transportation (USDOT) lists the construction of I-70 among the engineering marvels undertaken in the Interstate Highway System and cites four major accomplishments: the section through the Dakota Hogback, Eisenhower Tunnel, Vail Pass, and Glenwood Canyon. The Eisenhower Tunnel, with a maximum elevation of 11,158 feet (3,401 m) and length of 1.7 miles (2.7 km), is the longest mountain tunnel and highest point along the Interstate Highway System. The portion through Glenwood Canyon was completed on October 14, 1992. This was one of the final pieces of the Interstate Highway System to open to traffic and is one of the most expensive rural highways per mile built in the country. The Colorado Department of Transportation (CDOT) earned the 1993 Outstanding Civil Engineering Achievement Award from the American Society of Civil Engineers for the completion of I-70 through the canyon.

When the Interstate Highway System was in the planning stages, the western terminus of I-70 was proposed to be at Denver. The portion west of Denver was included in the plans after lobbying by Governor Edwin C. Johnson, for whom one of the tunnels along I-70 is named. East of Idaho Springs, I-70 was built along the corridor of U.S. Highway 40 (US 40), one of the original transcontinental U.S. Highways. West of Idaho Springs, I-70 was built along the route of US 6, which was extended into Colorado during the 1930s.