If you're someone who prefers to have your furry best friend by your side for all your outdoor adventures, it can be a bummer to plan a trip only to find out your chosen spot isn't dog-friendly. The good news is that while not all of the 63 national parks and 424 national park sites in the country allow dogs, many do! However, most have strict rules about where your pup can hike or stretch their legs mid-road trip. (Both for their safety and, in some cases, to protect endangered wildlife in the area.)