Yellowstone National Park, established on March 1, 1872, is the world's oldest National Park.
Yellowstone is famous for hosting more than 10,000-plus hot springs and geysers, the majority of the planet's total. Yellowstone's geothermal wonders are created by one of the world's largest active volcanoes; its last eruption caused a crater or caldera that spans almost half of the parks size. We can't forget about Yellowstone's most famous geyser, Old Faithful. Old Faithful erupts more frequently than any of the other big geysers and is still as spectacular as it was a century ago.
Experience Old Faithful, the most popular geyser in the world, and hundreds of other geysers and hot springs. Look for bears and wolves, elk and buffalo in the Lamar and Hayden Valleys. Hiking, camping, fishing, enjoying exhibits and films, and attending Ranger-led programs are among the many ways to experience Yellowstone.
The best times to see wild animals in summer are early morning and late evening. The Hayden Valley between Fishing Bridge and Canyon, and Pelican Creek east of Fishing Bridge are prime moose territory. Watch for bison in Hayden Valley, and waterfowl along its Yellowstone River. Watch for elk, bison, pronghorn, and coyotes in Lamar Valley, and for pronghorn in sagebrush flats near the North Entrance. Bighorn sheep frequent Mount Washburn in summer.
Yellowstone's vast collection of thermal features provides a constant reminder of the park's recent volcanic past. Indeed, the caldera provides the setting that allows such features as Old Faithful to exist and to exist in such great concentrations.
Yellowstone National Park, encompassing 2.2 million acres, is one of America's premier wilderness areas. Most of the park is backcountry and managed as wilderness. Over 1,100 miles (1770 km) of trails are available for hiking. However, there are dangers inherent in wilderness: unpredictable wildlife, changing weather conditions, remote thermal areas, cold water lakes, turbulent streams, and rugged mountains with loose, rotten rock.
The distribution of rocks and sediments in the park also influences the distributions of flora and fauna. The volcanic rhyolites and tuffs of the Yellowstone Caldera are rich in quartz and potassium feldspar, which form nutrient-poor soils. Thus, areas of the park underlain by rhyolites and tuffs generally are characterized by extensive, monotypic stands of lodgepole pine, which are drought tolerant and have shallow roots that take advantage of the nutrients in the soil. In contrast, andesitic volcanic rocks that underlie the Absaroka Mountains are rich in calcium, magnesium, and iron.
Bison are the largest mammals in Yellowstone National Park. They are strictly vegetarian, a grazer of grasslands and sedges in the meadows, the foothills, and even the high-elevation, forested plateaus of Yellowstone. Bison males, called bulls, can weigh upwards of 1,800 pounds. Females (cows) average about 1,000 pounds. Both stand approximately six feet tall at the shoulder, and can move with surprising speed to defend their young or when approached too closely by people.