How did Ronald Reagan do so well in Los Angels County?

[Del Tachi]

He carried LA County both times which is unprecedented for a Republican. I get he was from California but this is LA County we’re talking about not San Diego, or Orange. They won’t just embrace someone who was known to start the rise of conservatism just cause he’s from that state. Gerald ford and George H.W who both won California lost LA County.

As has been pointed out, Nixon won Los Angeles County in 1968 and 1972.  Eisenhower won it in 1952 and 1956; Dewey only barely lost in 1948.  LA County had an uninterrupted streak as a national bellweather between 1920 and 1984.  It didn't become a Safe D county until the 1990s.

[Del Tachi]

It's pretty obvious looking at certain county results that RR won hispanics.

Which counties?  Exit polls had Reagan losing the Hispanic vote in both 1980 and 1984.

I think Atlas is (once again) underestimating the amount of demographic transformation that's happened in a lot of urban/suburban counties over the past 30 years.  Los Angeles County was 40.8% non-Hispanic White in 1990, but only 26.5% non-Hispanic White by 2017.