 The route was created in 1997 when U.S. Route 63 (US 63) was rerouted along a new, four-lane expressway that subsumed part of a previous Iowa 23.The new Iowa 23 was signed along the two-lane road that was vacated by US 63.Iowa 23 begins at an intersection with Iowa 149 along the Mahaska–Keokuk county line north of Ottumwa.