Ohio State Route 15
State Route 15 is a north–south and east–west route in northwestern Ohio. Its southern terminus is at its interchange with U.S. Route 23/State Route 103 near Carey, and its northern terminus is at the Michigan state line north of Pioneer, where the route continues in Michigan as M-99. The route is signed east–west from Carey to Bryan, and it is signed north–south from there to the Michigan state line.
SR 15 is an expressway for its southernmost : where it runs concurrently with Interstate 75, where it runs concurrently with US 68, and the final as a stand-alone limited-access road until its junction with US 23. The final are part of a heavily traveled corridor providing the most direct route between Detroit, Toledo, Findlay, Marion and Columbus.
Image:OhioSR15.JPG|thumb|left|Eastern terminus near Carey
History
SR 15 was certified in 1923, along the current US 322, which replaced it in 1926.In 1926 the designation was reapplied to a route from Carey to the Indiana state line. In 1929 it was rerouted to Bryan, replacing parts of SR 9. It replaced the rest of SR 9 in 1931, rerouted along its current route to the Michigan state line.
In 1966, SR 15 was rerouted on an expressway from I-75 in Findlay to US 23 in Carey, its new southern terminus. The highway runs a few miles south of its previous routing, which was recertified as SR 568 the same year.