No, Yellowstone is a National Park, and it holds the historic distinction of being the first national park in the world, established by the U.S. Congress on March 1, 1872. While many people confuse the terms, there is a legal difference: National Parks are created by an Act of Congress to protect large areas of scenic, educational, and recreational value, whereas National Monuments can be created by a Presidential Proclamation under the Antiquities Act of 1906 to preserve specific "objects of historic or scientific interest." Yellowstone’s 2.2 million acres across Wyoming, Montana, and Idaho are managed by the National Park Service to preserve its unique geothermal features, such as Old Faithful, and its massive wildlife populations. In 2026, it remains the flagship unit of the American park system and is also a designated UNESCO World Heritage Site and an International Biosphere Reserve. While there are national monuments nearby, such as Devils Tower, Yellowstone has never been a national monument; it has always been a premier National Park since the very inception of the concept of public land preservation.