Interstate 70 (I-70) is a major Interstate Highway in the United States that runs from a park and ride near Baltimore, Maryland, to I-15 near Cove Fort, Utah. I-70 approximately traces the path of U.S. Route 40 (US 40, the old National Road) east of the Rocky Mountains. West of the Rockies, the route of I-70 was derived from multiple sources. The Interstate runs through many major cities including Denver, Kansas City, St.