State Route 315 is a north–south highway in central Ohio, mainly in the Columbus metropolitan area. It may be seen abbreviated as SR 315, OH-315, or simply 315. Its southern terminus is at the south junction of I-70 and I-71 in Columbus, and its northern terminus is at US 23 near Delaware. It is a controlled access freeway from its southern terminus to I-270. The controlled access section carries two or three lanes in each direction, depending on the location. North of I-270, it becomes a two-lane road. It roughly follows the Olentangy River for about two-thirds of its length. The route passes near The Ohio State University campus.

The section between Interstate 670 and Interstate 70 is known as the West Innerbelt, and is commonly referred to as such in traffic reports. The original name of this section was Sandusky Street.

Running in a north and south direction within Franklin county, commencing at the point where that state route crosses over King avenue and extending northward to the boundary of Franklin county and Delaware county.

Ohio 315's original southern terminus was in the Linworth suburb of Columbus. The route was extended to meet with I-71 in downtown Columbus, close to the OSU campus, in 1966. In 1976 it took the route of I-71 from there to I-70 when I-71 was rerouted to the eastern side of downtown Columbus. By 1983 the entire route from I-70 to I-270 was a freeway.

All exits are unnumbered.

An unsigned state route 315C exists which begins on the I-670 westbound ramp to Neil Ave, follows Neil south to the Goodale-Neil Connector and Goodale Ave, then up Olentangy River Rd and onto the ramp to SR 315 southbound, where it ends. It is not clear from the Straight Line Diagram whether SR 315C exists in both directions, or westbound only.

List of unused highways in Ohio