Yes they do. I am watching a beautiful full grown possum by my porch right now! -1:45am, Androscoggin County,Town of Lisbon. This summer my yard has many raccoons and skunks; this is my first up-close-and-personal possum experience. Remember to look up; they are climbers, like raccoons.
Maine is actually too far North for opossums to survive, however there have been isolated reports of opossums as far North as Toronto and Quebec.
I happened to look this up because I am from Lewiston and saw a opossum outside. I thought it was my imagination but I see him once a week. Strangely enough the first time I saw him I went outside because I heard gun shots. I saw him running across the street.