As I note in The Poacher's Son, Maine is a pretty big state — roughly the size of the other New England states combined — and the book spans a great deal of that real estate.
Maine Game Warden Mike Bowditch's district includes a portion of the midcoast, a district based around the fictional town of Sennebec that includes the Damariscotta, Rockland, and Camden regions.
Many of the places in this story don’t exist on the map of Maine (at least not under the names I have given them), but two important exceptions are the townships of Flagstaff and Dead River. In 1950 the Central Maine Power Company built a dam above Grand Falls and flooded the Dead River valley northwest of the Bigelow Mountains. Flagstaff and Dead River are gone, but sometimes, when the water is low on Flagstaff Lake, you can take a boat out and peer down at the ruins of what were once two vibrant North Woods villages. To anyone interested in learning more about these lost towns I recommend There Was a Land, distributed by the helpful people of the Dead River Historical Society.