State Route 605 (SR 605, OH 605) is a north–south state highway in central Ohio, a U.S. state. The southern terminus of State Route 605 is at a signalized intersection with U.S. Route 62 in the northeastern Columbus suburb of New Albany. Its northern terminus is also at a signalized intersection, this time with State Route 37 approximately 3 miles (4.8 km) to the southeast of Sunbury.

State Route 605 runs through the northeastern corner of Franklin County and the southeastern portion of Delaware County. The highway is not incorporated within the National Highway System.

This state highway first appeared in 1937. It originally followed the alignment that it currently occupies between U.S. Route 62 and State Route 37, then continued north from its current northern terminus along Delaware County Road 605 up to a junction with the U.S. Route 36/State Route 3 duplex in Condit. By 1995, jurisdiction of the portion of State Route 605 between State Route 37 and the U.S. Route 36/State Route 3 duplex was transferred from ODOT to Delaware County, who fittingly renamed the highway as County Road 605. As a result of this move, State Route 605 took on the routing that it does today.