The Wild River Wilderness area spans both New Hampshire and Maine and can be accessed by multiple trail heads in either state. Route 113 (open seasonally late May/early June until the snow begins to fall) travels through the Evans Notch in the White Mountain National Forest and has multiple trail heads that enable you to access the Wild River Wilderness Area. This wilderness area is relatively new and is one of my favorites in the country.
There are several established campsites in the Wilderness Area, most of which had shelters at one point that were taken down once it received the Wilderness designation. However, the areas are still established camping areas with tent cribbing and many have established fire rings and National Forest Service signage. I will try to add those camping areas and review them based on their names and not lump them into one review.
That being said, this particular review is focused on camping in the Wilderness outside of designated sites. In our household, we call this "bush crashing." In May of this year, the Dyrt magazine published a helpful article about this very thing and you can check it out here: https://thedyrt.com/magazine/lifestyle/free-camping-national-forests/
There is plenty of "dispersed" (aka bush crashing) available in the Wild River Wilderness. Just keep in mind that some areas are not open to camping, mainly Forest Protection Areas that are generally located within a 1/4 mile from trail heads and established designated campsites. Otherwise, just find a spot 100-200 feet from water and the trail and you're golden. On this particular trip we parked at the Wild River Campground (fee required to park here) and headed into the woods via the Wild River Trail. Once you're in the wilderness area, keep your eyes pealed for any flat-ish spot up from the river and you won't be disappointed.
Just remember, dispersed camping can be a little bit of a shock if you're used to rolling up to an established and/or maintained camping area. It will not look like what you may expect, so don't be disheartened or deterred. You can still make a cozy home for the night. Be sure to bring a stove to cook one, as fires are not permitted outside of designated sites. Also be prepared to dispose of your solid human waste per Leave No Trace principles (back a WAG bag or trowel). There's a lot to explore and with the ability to camp just about anywhere you want, there's no need to worry about mileage or a camp site being full. The world is your oyster when you hone the art of bush crashing!