I researched at the Western Kentucky site and found the following tidbit of information:
 The evolution of the nickname "Hilltoppers" is obvious to those who have seen the Western Kentucky campus.
The operations of Western Kentucky State Normal School were moved from its forerunner, Southern Normal School, to a commanding hill on the southwestern portion of Bowling Green on February 4, 1911. The move was completed as the entire student body marched to the new site, carrying various articles of school equipment.

Since the summit of "the Hill" rises 232 feet above nearby Barren River and the comparatively level plain that surrounds it, it was only natural that the athletes who represented the institution should come to be known as the "Hilltoppers."
Still, the name did not come into use until the 1925-26 school year. Prior to that, Westen teams were commonly referred to as "Pedagogues" or "Teachers" The first WKU uniform to bear the Hilltopper nickname was worn in 1927