High Quality Content by WIKIPEDIA articles! Interstate 70 (I-70) is an Interstate Highway in the United States that runs from Interstate 15 near Cove Fort, Utah, to a Park and Ride near Baltimore, Maryland. It was the first Interstate Highway project in the United States. I-70 approximately traces the path of U.S. Route 40 (and also the old National Road) east of the Rocky Mountains. West of the Rockies, the route of I-70 was derived from multiple sources. I-70 is the fifth longest Interstate Highway, after I-90, I-80, I-40, and I-10.