State Route 15 (SR 15) is a north–south and east–west route in northwestern Ohio. Its southern (eastern) terminus is at its interchange with U.S. Route 23/State Route 103 (US 23/SR 103) near Carey, and its northern (western) 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.

Quick Facts State Route 15, Route information ...

State Route 15
Route information
Maintained by ODOT
Length	102.312 mi[1] (164.655 km)
Existed	1926–present
Major junctions
East end	US 23 / SR 103 near Carey
Major intersections	US 68 in Findlay I-75 in Findlay US 224 in Findlay US 127 near Bryan US 6 near Bryan US 20A near Montpelier I-80 / I-90 / Ohio Turnpike in Holiday City US 20 in Pioneer
North end	M-99 near Pioneer
Location
Country	United States
State	Ohio
Counties	Wyandot, Hancock, Putnam, Defiance, Williams
Highway system
Ohio State Highway System Interstate US State Scenic
← SR 14 → SR 16
← US 22 SR 22 → US 23

Close

SR 15 is an expressway for its southernmost 19 miles (31 km): two miles (3.2 km) where it runs concurrently with Interstate 75 (I-75), three miles (4.8 km) where it runs concurrently with US 68, and the final 14 miles (23 km) as a stand-alone limited-access road until its junction with US 23. The final 17 miles (27 km) are part of a heavily traveled^{[citation needed]} corridor providing the most direct route between Detroit, Toledo, Findlay, Marion and Columbus.

This section does not cite any sources. (April 2019)

SR 15 was certified in 1923, along the current US 322, which replaced it in 1926.^{[citation needed]}

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.^{[citation needed]}

In 1966, SR 15 was rerouted on an expressway from I-75 in Findlay to US 23 in Carey, its new southern (eastern) terminus. The highway runs a few miles south of its previous routing, which was recertified as SR 568 the same year.^{[citation needed]}