Wikipedia:WikiProject U.S. Roads/Ohio/Historical information from the 1920s

Most of the information here is from [1] and [2].

The system of routes that exists today first appears on the 1923 ODOT map. The 1926 map is the first with city insets, and shows preliminary U.S. Routes but also the old State Route numbers. The 1927 map shows the effects of the renumbering.

State Route 1
, IN to Wheeling
- Now
  U.S. Route 40
State Route 2
, IN to PA
- Now
  U.S. Route 20
State Route 3
, Cincinnati to Cleveland
- Now
  U.S. Route 42
State Route 6
, Cincinnati to MI
- Now
  U.S. Route 24
State Route 7
, IN to Conneaut
- Now
  State Route 164
  , South Avenue, State Route 7
State Route 9
, Cincinnati to MI
- Now
  State Route 15
State Route 25
, Cincinnati to Friendship
- Now
  State Route 125
State Route 26
, Dunlap to Griffith
- Now Kemper Road,
  State Route 26
State Route 27, Cincinnati to Enterprise
- Now
  State Route 180
State Route 28, Cincinnati to West Jefferson
- Now
  State Route 142
State Route 74
, Cincinnati to south of Seaman
- Now
  State Route 32
State Route 124
, Sharon to Franklin
- Now Cincinnati Dayton Road, Dixie Highway (old
  U.S. Route 25
  )
State Route 125
, Le Sourdsville to Lebanon
- Now
  State Route 63
State Route 126, Hamilton to IN
- Now
  U.S. Route 27
State Route 127
, IN to Hamilton
- Now
  State Route 129
State Route 128, Cleves to Hamilton
- Now
  State Route 128
State Route 129, Cincinnati to IN
- Now
  State Route 126
State Route 130
, IN to Bridgetown
- Now Harrison Avenue (old
  U.S. Route 52
  )
State Route 131, Milford to Fayetteville
- Now
  State Route 131
State Route 132
, New Richmond to Williamsburg
- Now
  State Route 276
State Route 223
, northeast of Ross to McGonigle
- Now
  U.S. Route 27
State Route 224, northwest of Hamilton to IN
- Now
  State Route 177