Current Ohio highway marker.  Markers of three-digit highways are generally wider than markers of two-digit highways.
Current Ohio highway marker. Markers of three-digit highways are generally wider than markers of two-digit highways.

The following are articles about state highways in the U.S. state of Ohio. The Ohio Department of Transportation maintains a system of state highways, usually called State Routes (SR). Within the State of Ohio, state route markers consist of a white badge shaped like Ohio, often against a black background, with a black route number in the center. U.S. and Interstate highways are also classified as state routes in Ohio.

There are no state-numbered routes which duplicate an existing U.S. or Interstate highway in Ohio.