Standard Highway markers for Ohio
|Interstates||Interstate nn (I-nn)|
|US Highways||U.S. Route nn (US nn)|
|State||State Route nn (SR nn)|
The Ohio Department of Transportation (ODOT) is responsible for the establishment and classification of a state highway network which includes interstate highways, U.S. highways, and state routes.  As with other states, U.S. and Interstate highways are classified as state routes in Ohio. There are no state routes which duplicate an existing U.S. or Interstate highway in Ohio.
Ohio distinguishes between "state routes", which are all the routes on ODOT's system, and "state highways", which are the roads on the state route system which ODOT maintains, i.e. those outside municipalities,  with a special provision for Interstate Highways.  Besides the state highway network, there are various county and township road networks within the state.
This section needs expansion. You can help by adding to it. (June 2016)
|Interstate Highways: A list of interstate highways within Ohio.|
|U.S. Highways: A list of U.S. highways within Ohio.|
|State Routes: A list of all state routes within Ohio.|
|Ohio Turnpike: A toll road carrying Interstate 90, Interstate 80, and Interstate 76.|