You were right about my county, which was Ontario, NY. I'd say your county would be in Utah, with a sizable Mormon population, but one that was nowhere near majority status in that county. Your county would be whiter than the national average
This one is also fictional:
1980: Carter + 4
1984: Mondale + 3
1988: Bush + 0.4
1992: Clinton + 6
1996: Clinton + 8
2000: Bush + 4
2004: Bush + 7
2008: Obama + 2
2012: Romney + 1
2016: Clinton + 1
2020: Biden + 7
I'm gonna say it's a Upper Peninsula/North Michigan County with a sizable city or semi suburb.
Mine is real
2020: Biden +19
2016: Clinton +15
2012: Obama +18
2008: Obama +18
2004: Kerry +7
2000: Gore +16
1996: Clinton +16
1992: Clinton +5
1988: Bush +18
1984: Reagan +22
1980: Reagan +13
1976: Carter +2
1972: Nixon +26
1968: Nixon +5
1964: Johnson +30
1960: Nixon +3
1956: Eisenhower +23
1952: Eisenhower +9