Today, the Road Trip 1926 is going south from Indianapolis. When the Great Renumbering happened, the Indiana State Highway Commission had decided that south of Indianapolis include both 35 and 37, and that north of Indianapolis be less than 30. (This was put into place when the Allisonville Road north out of the city would originally commissioned SR 13.)
This road started at the Ohio River at Tell City. From there, it wound its way to Paoli. At Paoli, the number 37 was attached to the route of the Dixie Highway through Orleans, Bedford, Bloomington, Martinsville to Indianapolis. It had been cobbled together from several original state roads, including the Bluff Road (to Waverly) and the Paoli State Road. From Tell City north to St. Croix, the number 37 was given to original SR 14. From St. Croix to Sulfur, it was part of SR 16. And from Sulphur to Indianapolis, the old number had been SR 22.
Over the years, SR 37 has become one of the most bypassed routes in the state. Bypasses of Waverly, Martinsville, Bloomington, and Bedford were put in place over the years. Complete reroutes at Indianapolis/Smith Valley and north of Oolitic have been put in place. The reroute at Indianapolis is, for the time being, still accessible. The one at Oolitic is actually closed to traffic, and falls off into a quarry. I say for the time being, since SR 37 south of Indianapolis, like its section north of the city, is being consumed (as of this writing) by the construction of Interstate 69. Most of the interstate routing follows what is current SR 37, with the fragmented sections becoming less and less directly accessible in places.