Iowa 25 was created in 1926 as a replacement for Primary Road No. 16, which was redesignated further east. It originally connected US 30 to US 34 in Creston. In the early 1930s, it was extended south to Blockton by absorbing all of Iowa 184. By the end of the 1930s, the highway reached the Missouri state line, where it ended for over 40 years. In the late 1970s and early 1980s, the highway south of Iowa 2 was turned over to local jurisdictions.
