Yellowstone National Park, in the state of Wyoming was established on March 1, 1872, and is the first national park in the United States. It is known for its geothermal features, including Old Faithful geyser, and diverse wildlife including 67 species of mammals such as bison, elk, black bears, and gray wolves, as well as numerous birds, fish, reptiles, and amphibians. The park's rich ecosystem supports both large mammals and smaller species, making it a prime location for wildlife observation. Grizzly bears are also a significant part of Yellowstone National Park's wildlife, with an estimated population of around 150 to 200 bears typically weighing from 300 to 1000 pounds, residing within the park's boundaries. They are most commonly spotted in areas like Lamar Valley and Hayden Valley, especially during dawn and dusk when they are most active. Yellowstone National Park spans over 2.2 million acres across Wyoming, Montana, and Idaho, making it a popular destination for nature lovers and outdoor enthusiasts.