Interstate 70 enters Ohio just east of Richmond, Indiana. Immediately after crossing into Ohio, eastbound travelers are greeted by a unique teal-blue arch that spans the width of the freeway, with a "Welcome to Ohio" sign above the eastbound lanes. A sign thanking travelers for visiting Ohio is mounted on the other side of the arch for westbound travelers. Continuing eastbound, I-70 intersects Interstate 75 north of Dayton, followed by I-675 on the east side of Dayton. Springfield is the next city, site of Buck Creek State Park.
I-70 then encounters the largest city in Ohio, Columbus. Columbus is bounded by I-270, and is roughly centered around the intersection of I-70 and Interstate 71, which share the same asphalt through a notoriously congested 1.5-mile stretch locally known as the "South Innerbelt" or, more commonly, "The Split." The Split will be reconstructed within the next few years. Interstate 670 connects Port Columbus International Airport with I-270, I-71, and I-70. East of Columbus, I-70 passes through Zanesville and on to Cambridge, where it intersects Interstate 77. Continuing on towards West Virginia, I-70 intersects Interstate 470 just east of St. Clairsville. I-470 is primarily used for through traffic, as it is actually shorter to travel I-470 through Wheeling than to continue on I-70.
In March 1995, a hole (from a former coal mine) opened up on the eastbound side of I-70 in Guernsey County near Old Washington, causing traffic to be rerouted onto US 40 between Old Washington and Cambridge for several months.