In the U.S. state of Ohio, Interstate 70 provides access between Indiana and West Virginia.

Along its path through Ohio, Interstate 70 passes through the following counties: Preble, Montgomery, Clark, Madison, Franklin, Fairfield, Licking, Muskingum, Guernsey and Belmont County. As an Interstate highway, by default, Interstate 70 is a part of the National Highway System, a network of highways deemed most important for the country's economy, mobility and defense.

Interstate 70 appeared on the original AASHTO interstate route numbering map from August 14, 1957. It was envisioned as a modern upgrade of the old National Pike (US-40), the main east–west route through the heart of the state, built closely parallel to, but on a separate alignment as the then overburdened and obsolete highway. The 21-mile (34 km) section between Kirkersville and Gratiot (current Exits 122 - 142), was the first new construction opened to traffic (1959). At that time, the highway was accessed at both ends via temporary at-grade intersections with the old National Pike, with I-70 and US-40 sharing the same carriageways.

Once the road was extended westward towards Columbus by 1968, access was routed to Exit 122, with the western 1-mile (1.6 km) access road continuing US-40 back to the old National Pike becoming part of OH-158 (though the westbound lanes were abandoned). The following year, the highway was opened eastward to Zanesville, with a new interchange, Exit 142, at Gratiot. The at-grade intersection with the old National Pike was subsequently blocked off, to be erased by years of overgrowth. The US-40 designation was returned to the Pike around the same time, replacing the temporary OH-440 designation.

In February 2013, an 11.18-mile segment of I-70 running through Franklin, Fairfield, and Licking Counties was named by the National Asphalt Pavement Association as the winner of the 2012 Sheldon G. Hayes Award for the best asphalt pavement in the country.

List of unused highways in Ohio