List of Interstate Highways in Ohio

There are a total of 21 Interstate Highways in Ohio, including both primary and auxiliary routes. With the exception of the Ohio Turnpike (which carries portions of Interstate 76 (I-76), I-80, and I-90), all of the Interstate Highways are owned and maintained by the U.S. state of Ohio through the Ohio Department of Transportation (ODOT); however, they were all built with money from the U.S. federal government. The road miles of these 21 Interstates add up to a total of 1,572.35 miles (2,530.45 km). Ohio has more route miles than this, most of which comes from I-80 running concurrently with I-90 for 142.80 miles (229.81 km). The Interstate Highways in Ohio range in length from I-71, at 248.15 miles (399.36 km), all the way down to I-471, at 0.73 miles (1.17 km).

As of 2019, out of all the states, Ohio has the fifth-largest Interstate Highway System. Ohio also has the fifth-largest traffic volume and the third-largest quantity of truck traffic. Ohio ranks second in the nation in terms of the number of bridges for its Interstates.