As of 2026, you do not need a reservation to enter Theodore Roosevelt National Park for general sightseeing or hiking. Unlike some of the "overcrowded" parks like Zion or Arches, this North Dakota gem allows you to simply drive up to the gate, pay your entrance fee (or show your America the Beautiful pass), and enter. However, reservations are strongly recommended for camping. The park’s two main campgrounds, Cottonwood (South Unit) and Juniper (North Unit), fill up quickly, especially during the summer months. You can reserve about half of the sites at Cottonwood via recreation.gov, while the others remain first-come, first-served. If you are planning a backcountry trip, you will also need a permit, which is free but must be obtained in person at a visitor center. For 2026, the park has also noted that certain special events, like the "America 250" celebrations, might require specific activity permits, so it's always wise to check the "Current Conditions" on the NPS website before your trip to see if any temporary closures or event-based restrictions are in place.