Bear Brook State Park spans more than 10,000 acres in Allenstown and is the largest developed state park in New Hampshire. Its museum complex of Civilian Conservation Corps buildings is listed on the National Register of Historic Places. Forty miles of trails serve hikers, mountain bikers, equestrians and snowmobilers, and visitors also swim, fish, canoe and shoot archery. The Beaver Pond campground has 101 sites, and there are cabins at Bear Hill Pond and a shelter at Smith Pond. Operations are seasonal. The campground runs from late April to late October, and the beach and other facilities open on weekends before full-time summer service.