Polls of important counties

[Alcon]

All polls of counties, congressional districts, and the like have tiny sample sizes and are meaningless.

That's not necessarily true.  We occasionally get polls at the county level (mostly for novelty), and it's not uncommon to get a full-fledged, standard poll of a congressional district.  Although, like HillOfANight says, there's really no reason to take the county polls over state polls when predicting the state's presidential results.