Late but there's beavers in the smaller pond at the Catmount State Forest in Colrain. I hike a lot in Western Mass and Southern Vermont and that's the only place I've ever seen them. I'm sure there are some places I don't know about though.

Park at the bottom of S. Catamount Road and hike up the hill. You'll come to a small pond on the left hand side of the trail before the path to the larger pond splits off. There were beavers there the last two times I was there.