Running for 94.835 miles (152.622 km) through the state, SR 15 is maintained by the Indiana Department of Transportation (INDOT).

Dating back to the before the state road system, the corridor that SR 15 takes today was part of the Hoosier Dixie Highway.

SR 15 was moved to its modern routing in late 1926, running from Marion to Goshen.

In late 1940s and early 1950s, SR 15 was rerouted between La Fontaine and Wabash, while the route was extended south from Marion to Jonesboro.

The road heads northwest, crossing a railroad track before entering Marion, passing east of Indiana Wesleyan University.

Past La Fontaine the road passes through an intersection with SR 124 before entering the city of Wabash.

While concurrent with Canel Street SR 15 has its lowest AADT at 3,123 vehicles per day on average measured in 2016.

The one-way pairs end with SR 15 heading north on Cass Street and leaves the historic district.

SR 15 heads north, passing a landscape of residential neighborhood, before bending to become northwest-southeast and having an intersection with US 24 Business.

North of Silver Lake the road passes west of Claypool before entering Warsaw.

Detroit Street heads north passes through commercial landscape, leaving downtown and having an interchange with US 30.

North of the railroad tracks the road enters downtown Bristol and turns east onto SR 120.

This highway ran from Marion to Goshen, routed along SR 13 between Wabash and North Manchester.

The first is injunction with the US 33 bypass of downtown Goshen, when completed SR 15 will be moved west of the Elkhart County Courthouse onto Third Street.

[21] The second project will take place during 2018 and will sign a truck route to avoid downtown Bristol.

The entire route passes through industrial land while avoiding the Downtown Wabash Historic District.