 Before 1963, the section of present-day SH-45 between SH-58 and SH-132 was part of the original SH-38.In 1963, all of this SH-38 west of Carrier was renumbered to SH-45 (a north–south section of SH-38 that connected Carrier to US-60 became part of a SH-132 extension).The same year, SH-45 was extended westward to Waynoka.