Trinity County mostly voted Democratic (with the exception of Eisenhower) until the 1970s, then became reliably GOP. Recently, it has started to vote Democratic occasionally (like in 2008). What’s the reason for this?
Until recently it has had horrific unemployment (20% in winter, 14% in summer). It is still high. It appears to have some big population swings.
From 1950 to 1960 +91%.
From 1960 to 1970
From 1970 to 1980 +56%.
The boom in the 50s may have been during construction of Trinity Dam. An increase from 5000 to 10000, might only take 1000-1500 workers with families along with service workers.
I don't know what triggered the recovery in the 1970s. More timbering? Commercial gold mining? The area is known for its recreational place mining - along with enforcement of mining claims. Perhaps going off the gold standard triggered interest. Weaverville at one time had a Chintatown with 2000 persons.
Wage income is really flat compared to California. So you probably have a lot of people just getting by. Maybe they do a little bit of construction work, or work your claim. Maybe you like the isolation. But then finally give up and get a job in Redding. So you may have a lot of population transition, rather than people changing their politics.
