The SR 202 designation was applied in 1923. Originally, the highway followed the majority of its present routing, from its southern terminus in downtown Dayton to its junction with SR 41, at the time designated as SR 70. It then followed the current SR 41's alignment northwest into downtown Troy, then crossed the Great Miami River concurrently with SR 55. SR 202 then split from SR 55, and was routed along Market Street heading northeast. The state highway then followed what is today known as County Road 193 (CR 193), heading east from Troy into Champaign County. It came to an end at SR 55 southwest of Urbana. In 1925, the entire east–west portion of SR 202 along the current CR 193 was removed from the state highway system. Consequently, the highway was shortened to its present alignment between Dayton and the current SR 41 junction.
