Eightmile Rd. (Wasco County Road 182)
(Seufert to near Rice)
(near Rice to Shaniko Jct.)
Tygh Valley Rd. and Old US-197
(within Tygh Valley)
Old Wapinitia Rd.
(Wapinitia Jct. to Maupin)
OR-23 was created with the advent of the state highway system in 1932 and ran from Seufert (near The Dalles) to Wapinitia Jct. (near Maupin), running along a portion of the Dalles-California Highway #4 from US-30 to OR-50. The route was extended in 1950, when OR-50 was shifted onto the new Warm Springs Highway #53 and off of the Wapinitia Highway #44 and a portion of the Dalles-California Highway between Wapinitia Jct. and Shaniko Jct. (US-97); the Wapinitia Highway became OR-52, and stayed that way until it became an extension of OR-216 in 1958. In 1952, with the completion of a bridge between The Dalles, OR and Dallesport, WA, the entire route of OR-23 became US-197, what it's remained ever since; OR-23 was effectively retired.
There are three former alignments of OR-23 still accessible by car along or from US-197. The first alignment, shown in red, started in Seufert where the current I-84 is now, continuing along Eightmile Rd. until it joined with what is now US-197 near Rice. This route was still in use when US-197 was routed over it as well as the new bridge linking The Dalles and Dallesport, and was bypassed sometime in the early 1960s; US-197's new route was never OR-23.
The second alignment runs through the heart of Tygh Valley. This routing, shown in green, started at the current US-197 north of town, continued through town (surviving as Tygh Valley Rd.), then curved south of the city (surviving as Old US-197) until it rejoined the current US-197. As with all curvy alignments through the hearts of small towns, this alignment (as well as Tygh Valley) was bypassed sometime in the early 1960s; US-197's new route was never OR-23.
The third alignment runs between Wapinitia Jct. and Maupin and is shown in blue. However, it is only a possibility that this section of road was OR-23. It could've been bypassed by what is now the current alignment of US-197 by 1950, when OR-23 was extended to Shaniko Jct. This roadway was definitely OR-50 beforehand, and possibly US-197 after OR-23 was decommissioned. If it was OR-23, it only would've been so between 1950 and 1952.