Baxter State Park [1] operates ten campgrounds, eight of which have drive-in sites. The byzantine reservation system employed by the park is complicated enough to stymie the most experienced tax law attorney. The upshot is that reservations can be made by mail or in person at the park’s headquarters (64 Balsam Dr., Millinocket) until 10 days before the date of arrival, and by phone (207/723-5140) up to 14 days before arrival.
Most of the campgrounds are open from mid-May to October, and popular sites, such as Roaring Brook and Abol campgrounds, fill up fast. Rates for lean-to and tent spaces are $10 per person per night with a $20 minimum; cabins are $27 per person, with minimums depending on their size. Gaslights and firewood are included in the fee.
Also scattered throughout the backcountry are dozens of lean-to sites available to hikers for free; advance reservations are required.
Links:
[1] http://www.moon.com/destinations/new-england/maine/downeast-and-the-north-woods/the-north-woods/baxter-state-park