Some thoughts:
CA: Berkeley
CO: Boulder
IL: Evanston
IA: Iowa City
KS: Lawrence
MD: Takoma Park
MA: Cambridge
MI: Ann Arbor
NJ: Princeton
NY: Williamsburg in Brooklyn
OR: Portland
TX: Austin
VT: Brattleboro
VA: Arlington
WA: Seattle
WI: Madison
How accurate is this? And what would it be for other states?
Williamsburg contains quite a lot of *extremely* Trump precincts in South Williamsburg (some over 90% Trump) so that won't the answer for New York. The answer for New York is probably something like the West Village in Manhattan or Prospect Heights in Brooklyn.
