North Cascades National Park is almost entirely protected as wilderness, and so the park has few structures, roads or other improvements. Visitors wishing to drive to a campground must do so in the adjacent national forests or national recreation areas. Camping inside the park requires hiking in by trail, horseback or boat, and camping is regulated by a permit system to ensure the wilderness is not over-exploited. Mountaineering is popular in the park and only unobtrusive clean climbing is allowed.