Most national parks, as well as other federal lands administered by the National Park Service, are not pet-friendly, and those planning to visit the parks should consider leaving their pets at home. Pets are usually prohibited on hiking trails, especially in the more popular parks, in the backcountry, and in buildings, and must always be leashed. Essentially, this means that if you take your dog or cat into the parks, the animal can be with you in the campgrounds and inside your vehicle, and you can walk it in parking areas, but that's about all. It's no fun for you or your pet.
Aside from regulations, you need to be concerned with your pet's well-being. Pets should never be left in closed vehicles, where temperatures can soar to over 120°F (49°C) in minutes, resulting in brain damage or death. No punishment is too severe for the human who subjects a dog or cat to that torture.
Those who do decide to take pets with them despite these warnings should take the pets' leashes, of course; carry plenty of water (pet shops sell clever little travel water bowls that won't spill in a moving vehicle); and bring proof that the dogs or cats have been vaccinated against rabies. Flea and tick spray or powder is also important, since fleas that may carry bubonic plague have been found on prairie dogs and other rodents in some parks, such as Mesa Verde and Bryce Canyon.
The Inside Scoop for Pet Owners -- Although pets are not permitted on the trails or backcountry in most national parks, those traveling with their dogs can hike with them over trails administered by the U.S. Forest Service and Bureau of Land Management, as well as some of the state parks that are adjacent to many national parks.
Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.