Actually two of them. The first one, which is the one seen in these pictures, was found on the road in front of my house. At first I thought it was dead but when I tried to pick it up with a rake it started snapping at me and moving. Eventually I got it on the rake and removed it to the woods to die (some of its intestines were hanging out) I turned around to find my 7 year old yelling that he had found another one. This one was most definitely alive and just basking in the sun near my little "pond". Getting near it, it rapidly reared up and then slid down the rocks into the pond, swimming very well and entering some cave under the rocks in the water.
Both were quite aggressive when disturbed raising their heads up off the ground a few inches and snapping rapidly at whatever was bothering it (in this case a plastic rake).
I didn't know what kind of snake it was at first (obviously not a rattler) but definitely the largest snake I'd ever seen in the "wilds" of NH as they were each about 3 feet long and quite thick. Looking them up after the fact it appears they are generally common throughout NH though this is the first I've seen of one (or two!)
The frogs, crayfish and small fish we have in our stream are likely their favorite meals while the big snapping turtles we see every year likely love to feed on these snakes. Ahh...the circle of life...