The recreation area encompasses 67,000 acres of mountain ridge, forest, and floodplain on both sides of the Delaware River in the states of New Jersey and Pennsylvania. Among the more surpising species of animals in the park are black bear, timber rattlesnakes, bald eagles, and, recently, nesting peregrine falcons. Ecosystems include hemlock ravines with bountiful rhodendron and ridgetops with prickly pear cactus.
Forty miles of the Middle Delaware River are within the park, as well as trout streams, lakes, ponds, and some of the highest waterfalls of either state. Water quality is exceptional in this section of the valley.The river's path through the mountains includes the S-curves of Walpack Bend and the Delaware Water Gap.