State Road 13 (SR 13) is a north–south state road in the US state of Indiana. The southern terminus is at an intersection with U.S. Highway 36 (US 36) and SR 67, in the town of Fortville, and its northern terminus is at the Michigan state line. At its northern end, signage for SR 13 ends at the interchange with the Indiana Toll Road; the highway continues unsigned for an additional 0.6 miles (0.97 km) running concurrently with US 131 to the state line. The state road runs through six counties in central and north-central Indiana mostly through rural farm fields and small towns.