There are many COE camping areas east of Mississippi also locations in the Green Mountain National Forest in Vermont and many state owned locations in the Adirondack Mountains. I can't remember all the websites that cover the subject. Google them up for sites. There are also forest service sites in the White Mountains of New Hampshire.
The Maine Northwoods also has a lot of wilderness sites available...details at any of the many entrance gates. There is an entry gate with information in Ashland, Maine and also the "Telos" gate near Mooshead Lake also Millinocket, Maine. Their are many such entry gates. A small entry fee is charged. These vast areas (millions of acres) are owned by wood, lumber and paper product companies who have built an elaborate network of gravel roads that provide access. They own the roads and their log trucks have right of way therefore you must yield when they approach.
The area is patrolled by the Maine Warden Service. The entire zone has no phone service, no electricity and covers millions of acres in northern Maine up to the Canadian boarder. I would avoid that region in the winter months.