Yellowstone Dog Policy
Yellowstone National Park is Not Dog Friendly
Situated on the Yellowstone Caldera, the park has an expansive network of geothermal areas including boiling mud pots, vividly colored hot springs such as Grand Prismatic Spring, and regularly erupting geysers, the best-known being Old Faithful. The yellow-hued Grand Canyon of the Yellowstone River contains several high waterfalls, and four mountain ranges traverse the park. More than 60 mammal species including timber wolves, grizzly bears, black bears, lynxes, bison, and elk make this park one of the best wildlife viewing spots in the country.
Yellowstone National Park is not a very dog-friendly national park. Dogs are not allowed on any trails, and in the most attractive areas of the park. Dogs are allowed along roads and in the campgrounds, however. Dogs may not be left unattended except in some campgrounds in RVs.
Bringing a dog to Yellowstone typically means missing out on most of the park, unless you have multiple people, and can have someone stay behind to watch your dog.
Dogs are allowed at front-country campgrounds on a leash no longer than 6'. Dogs can be left unattended in RVs as long as they're quiet. Dogs cannot be left unattended in tents.
In addition to the the campgrounds in the table below that are reservable on recreation.gov, Yellowstone has the following campgrounds that allow dogs:
 Overview text from the Wikipedia article List of national parks of the United States, which is released under the Creative Commons Attribution-Share-Alike License 3.0.All other text and images, except where noted, copyright ASR Concepts, LLC, all rights reserved.