California State Route 206 was a short eight-mile State Highway which existed in the San Bernadino area. Prior to the 1964 State Highway Renumbering what would become California State Route 206 was part of the original US Route 66 Business Loop via Kendall Drive and E Street towards downtown San Bernardino. As defined in 1964, California State Route 206 began at California State Route 30 in San Bernadino and terminated at Interstate 15 in Verdemont. California State Route 206 was ultimately deleted from the State Highway System in 1991. The original US Route 66 Business Loop can be seen co-signed with California State Route 18 at the I Street Overhead along 5th Street in San Bernardino circa 1951.
https://www.gribblenation.org/2022/07/former-california-state-route-206-and.html?m=1