Los Angeles used to have the reputation of a conservative city. That changed in the 1960s and 1970s, much moreso in the 1990s. Goldwater performed better in LA County than he did nationally.
If I recall correctly, Goldwater "only" lost Los Angeles County by about 14% in 1964. He did better throughout all of Southern California than he did nationally, and won Orange and San Diego Counties outright (the former by double digits). Goldwater also ran ahead of his national average throughout the entire American Southwest, narrowly winning his home state of Arizona and getting over the 40% mark in New Mexico and Nevada (and losing Utah by slightly under 10%). Johnson, conversely, ran ahead of his national average throughout Northern California, particularly in many counties (i.e. Plumas) that were ancestrally Democratic, dating back to the days of the New Deal and even earlier.
