This past month I paid a visit to CA 371 which is a 21 mile connecting route between CA 79 and CA 79. CA 371 is a post 1974 renumbering of what was the eastern segment of CA 71 which was extended during the 1964 State Highway Renumbering. CA 371 has origins as Legislative Route 277 which was added to the State Highway System in 1959. Interestingly it appears that LRN 277 was intended to be a brand new alignment much the Division of Highways adopted to assume maintenance of the existing route of Cahuilla Road and Kenworthy-Bautista Road by 1962.
https://www.gribblenation.org/2019/11/california-state-route-371.html