Page "California State Route 12" Paragraph 14

Before the 1964 renumbering, this route was signed as Sign Route 12 for most of its length.

However, SR 12 was designated as LRN 51 from SR 116 to SR 121 before the 1964 renumbering.

Portions of the route from SR 29 to I-80 ran concurrently with State Route 29 or with State Route 37 ; this was also LRN 8 and a former routing of U. S. 40.

The portion from I-80 to then-US 99 was designated as LRN 53 in 1919 ; from US 99 to SR 49, it was designated as LRN 24.