So in 1944, when Crosby hit No. 1 with a jaunty song called “San Fernando Valley,” it was no surprise that GIs heard it as a call to build their postwar lives in a new Eden out west.

During 1943 and 1944, World War II infiltrated all aspects of life in the San Fernando Valley. The Van Nuys News, predecessor of the Los Angeles Daily News, reported on community campaigns for ...