Christopher J. Kempf created this very cool map looking at the 2012 presidential election results in the Northeast on a municipal level, which gives us a very fine-grained view of the voting patterns:
This is overall one of the most liberal and Democratic-leaning regions in the US, but you can still see clear patterns within it — notably that big cities are much more Democrat-friendly than rural areas.
The huge exception to this is Vermont (and the portion of western Massachusetts that abuts Vermont), where Barack Obama won virtually every town no matter how small and where huge swaths of the state are deep, dark blue despite the total absence of any kind of city. This is Bernie Sanders country, and it's kind of a strange place — not only much more liberal than the typical American place, but much more rural (and whiter) than the typical liberal place in America. That accounts for some of Sanders's earlier fumbling around Black Lives Matter but also for some of his appeal.
There's almost nobody in the US Senate who represents such a uniformly liberal place — even Massachusetts has significant Republican pockets and regional divisions. That encourages Sanders to talk about his ideas in a frank, unapologetic, and unhedged way that American liberals rarely hear from practical politicians.