All-County Sweeps Since 1932

[Skill and Chance]

Arizona's Democratic dominance during the FDR era is pretty impressive.

Mining communities were near unanimous Dem back then, and due to the low population in general, they were large enough to dominate statewide in most Interior West states pre-WWII.  Post-WWII, rapid expansion of the metros with R-leaning suburbs swamped them, even though the resource extraction areas themselves didn't switch sides until much later (generally 1970-2000, although Butte, Montana still votes Dem today).