State Road 37 (SR 37) is a major route in the U.S. state of Indiana, running as a four-lane divided highway for 110 miles of its course. At one time, the route ran from the southwest corner of the state to the northeast corner. In the pre-Interstate Highway era, Indiana 37 was the most direct route between Fort Wayne and Indianapolis. Interstate 69 has supplanted it as a through route, and State Road 37 now consists of two disconnected segments. The longer segment starts at Tell City on the Ohio River and ends in Marion in north central Indiana. The other segment in northeastern Indiana runs from Interstate 469 near Fort Wayne to the Ohio state line.