Ohio State Route185 underwent several changes in history,from replacing SR 120, being extended to US 127 by 1953, and finally realigning back to its eastern terminus in 2011.
Replacing what had been designated SR 120, the highway ran from its intersection with GreenvilleSt. By 1953, when US 127 was re-routed onto a more direct alignment in northern Darke County, SR 185 was extended a short distance west to its current western terminus at the then newly-realigned US 127. On September 26, 2011, SR 185 was re-aligned from its former eastern terminus at the junction of US 36 and SR 66 in downtown Piqua. 
