California State Route 72 is a State Highway located in the Los Angeles Metro Area and a component of early US Route 101. The Legislative definition of California State Route 72 presently begins at Interstate 605 in Whittier and follows Whittier Boulevard to California State Route 39 near La Habra. Prior to 1953 US Roue 101 followed Whittier Boulevard, Spadra Road (now Harbor Boulevard) and Los Angeles Street (now Anaheim Boulevard) from Los Angeles to Anaheim. The original surface corridor of US Route 101 was repurposed as California State Route 72 during the 1964 State Highway Renumbering. California State Route 72 as originally defined during the 1964 State Highway Renumbering spanned from Interstate 5 in Anaheim to the original California State Route 245 at Downey Road near Los Angeles. Below the current scale of California State Route 72 can be seen contrasted to it's original size seen on the 1965 Division of Highways Map.
The history of California State Route 72 and early US Route 101 between Los Angeles-Anaheim
The era of State Highway Maintenance through in the Los Angeles-Anaheim corridor would begin with the 1909 First State Highway Bond Act which was approved by voters in 1910. One of the highways approved through the 1909 First State Highway Bond Act was a 481.8-mile highway originating at the City Limits of San Francisco which terminated in San Diego. This highway would ultimately come to be known in time as Legislative Route Number 2 ("LRN 2").
The January 1915 California Highway Bulletin references LRN 2 from the Los Angeles/Orange County line to Anaheim as being completed between to State standards.
Prior to 1933 the State of California could not actively maintain highways in incorporated cities. LRN 2 can be seen following Whittier Boulevard, Spadra Road and Los Angeles Street from the Los Angeles city limit to Anaheim on the 1917 California State Automobile Association Map. LRN 2 can be seen passing through the communities of Montebello, Whittier, La Habra and Fullerton.
LRN 2 between Los Angeles and Anaheim is shown as part of the Old Spanish Trail on the 1924 Rand McNally Map of California.
The August 1924 California Highways & Public Works references the ongoing widening of LRN 2/Whittier Boulevard to 56 feet in width.