Located on the south banks of the Chilliwack River under a grove of western redcedars, Douglas firs, and bigleaf maples, Allison Pool Recreation Site Group Campground, is as the name implies, ideal for large group gatherings.
In fact, there is only one site (made up of seven individual sites), and the entry gate remains closed until reservations are made, so unfortunately the campsite isn't ideal for the spontaneous at heart. Its also less than ideal for families or those with young kids as the campground only provides picnic tables and one vault toilet. If you're the kind of group that needs potable water, showers, and a few other niceties, you'd best to look elsewhere.
All that being said, the campground's setting alongside the Chilliwack River and the Allison Pool (a swift moving and deep pool in the river perfect for strong swimmers) is ideal for groups seeking a rustic and private setting away from the hustle-and-bustle of more established campgrounds.
Note: Allison Pool Recreation Site Group Campground is open year round. Reservations are required, and the entrance gate is closed otherwise. Tamihi Creek East Recreation Site Campground, located 3.6 kilometers downstream, is the nearest source for potable water.