Thumbs up on the County map. Thanks!

I suggest that rather than use the simple "number of cases" as the metric to select the map colors, you switch to using either "per sq mile" or "per population."

Consider:
Peoria 85382: it has 71 cases for 40454 people, making it just worse than...
Phoenix 85003: it has 12 cases for 9369 people

But comparing either to the 21 cases in Tempe 85282 which has both more area and more population (48671) isn't very clear from the map. Tempe 85282 has one case for every 2318 people. Peoria 85382 and Phoenix 85003 have one case for every 570 and 781 people respectively, making them arguably 4 times more affected (and infected) than Tempe.

Other people have suggested having a wider range (more) colors on the map. I agree with that, too. But this isn't mutually exclusive of my suggestion here--if you can, do both!

Thanks!