The Eastern and Central US has the Rough Green Snake (New Jersey and south) and the Smooth Green Snake, in the Northeast. These skinny bug-eaters are often referred to as "Grass Snakes," although both like to climb in vegetation.
They are so well-camouflaged that they are rarely seen, and they tend to freeze when disturbed. I think I once saw a Rough in a bush in southern CT, but I can't swear it was a Rough because it moved too quickly for me to grab it to check it's ID.
I love seeing snakes in New England. We don't have enough of them except for the regular Garter Snakes that always startle you when they are curled up in a Zucchini plant and the gigantic Black Snakes on stone walls and in the sand on Cape Cod. Did I ever mention the time my Mom killed a Milk Snake with a hoe (mistaking it for a Copperhead) while we batch of kids were playing in the grass? A mythical moment.
Rough Green Snake hunting in a Blackberry patch: