The map comes to me via Barry McMillion, who deserves the credit. Bsking sent it along.
To those outside of New England, this might be interesting only to note that there are strongly red sections even in very blue states. Even I, who am a geography nut, have to strain at some of these sections to figure out which towns are intriguing exceptions in their areas. The yellows tend to be wealthy towns. It also pays to remember that "rural" in New England does not automatically suggest farming - it sometimes just means "almost empty." So I wouldn't work too hard to get your head around what is going on in the minds of those pale and dark purple towns in Maine. They are 50-50 red/blue to begin with, so small movements in the electorate can flip them. They have few people, and include much rural poverty, folks depending on five side businesses and food stamps to get by. You can also see why we in NH consider the towns along the Connecticut River to be practically part of Vermont, and why I call them the West Coast of NH. No surfing or beaches though.
Many of the darker blues and reds have more population, and illustrate the continuity of voting for the Democrat even if they hated Hillary (as many in Vermont do after her treatment of Bernie) or voting for the Republican even if they hated Trump. Donald captured an interesting group that other candidates might not have, but most of his votes still came from people whose families have voted Republican since Harding.
As for those who switched, I am intrigued by that dark purple stretch that covers Eastern Connecticut (fancy prep schools there), Western Rhode Island, and Central Massachusetts. It is not broken up by blues that much or yellows at all, but by red, even creeping over the border into NH. I don't have a good sense for who those people are, but they look like a consistent demographic a candidate might cultivate. (For those who like such things, there is a similar cluster at the borders of Illinois, Iowa, Minnesota, and Wisconsin that was usually blue but not deeply so. If a candidate could figure out what they have in common and win them over, s/he could make deep inroads in four states. Trump sort of did that, and it was key to 2016. Holding rallies in that 100-mile radius wouldn't hurt him going forward, and I have to think some Democratic strategist (they have some very good ones) has figured this out for later, though it's pretty useless in the primaries.)
Interesting patterns you might notice are welcome.