Listed below are links to campgrounds in the region as well as to areas nearby. Almost all require some sort of reservations, however, some back-country no-reservations camping is available via Appalachian Trail so let's start with that first!

Appalachian Trail (free/no reservations)
The Appalachian Trail in Connecticut and Massachusetts has numerous campsites you can rest for the night. 15 sites in Connecticut along 52 miles of trail and 15 in Massachusetts in about 90 miles of trail. You will need to hike in to the campsites.

Appalachian Trail camping is free! First-come, first-served is the rule though it is custom to give up a nice cabin lean-to space if it is full and a Georgia-to-Maine hiker needs the spot. In that case you should pitch your tent nearby as space shouldn't be an issue outside of lean-to cabin. Connecticut - (south to north direction): Ten Mile River (mile 3), Schaghticoke Mountain (mile 8.3), Stewart Hollow Brook (mile 18.5), Stony Brook (mile 18.9 - group sites available), Silver Hill (mile 21.7 - group sites available), Caesar Brook (mile 25.1 - group sites available), Pine Swamp Brook (mile 28.5 - group sites available), Sharon Mountain (mile 30.9), Belter (mile 33.7), Limestone Spring (mile 40.8 - group sites available; side trail leads to camp), Riga (mile 48.3), Ball Brook (mile 48.9 - group area available), Brasssie Brook (mile 49.5 - group sites available), Sages Ravine (mile 52.3 - group sites available).

Massachusetts - (south to north direction): Laurel Ridge (mile 2), Race Brook Falls (mile 4.7 - short hike off trail to camp), Hemlock Shelter (mile 6.7), Glen Brook (mile 6.8), Tom Leanord Shelter (mile 21.1), Wilcox North (mile 26.4), Wilcox South (mile 28.2), Shaker, Upper Goose Pond Cabin (mile 42.2 - cabin is closed winter but tents allowed all year), October Mountain Shelter (mile 51), Kay Wood Shelter (mile 59.8), Chrystal Mountain (mile 67.5), Noepel Shelter (mile 76.7) Wilbur Clearing (mile 83.3), Sherman Brook (mile 88.1).

The A.T. is maintained by the Appalachian Mountain Club and you can learn all about camping along the trail from them. The have local chapters (Connecticut AMC, Massachusetts, New York/New Jersey) and each chapter has volunteers and teams at work to maintain and run their areas. If you have any questions or need advice you should contact them.

Visit Appalachian Mountain Club website and then click on a 'Chapters' to find CT, MA, ME, NH, NJ, NY, and VT clubs. If you join the AMC you get some great benefits from doing so such as reserving certain shelters that non-members don't have access too.