The original route of what would become, on 1 October 1926, SR 45 was actually proposed in two sections. The northern section of the road would be marked as an authorized addition to the state road system. The southern section already had been a part of that system.
The official description, as released in the newspapers of the time, was as follows: State Road 45 – In two sections, Bloomington to Cincinnati, Ind., in Monroe and Greene Counties, and Loogootee to Rockport. (The Bloomington – Cincinnati (Ind.) part and a section between Loogootee and Haysville are new roads. The part between Haysville and Rockport is now called State Road 18.)