Bubbling mud-pots, mysterious fumaroles and steam spewing geysers are what make Yellowstone National Park famous, but visitors will also discover a vast land with thunderous waterfalls, majestic mountain ranges and a two million acre stronghold for wildlife. Formed eons ago when the earth's crust fractured, super-hot magma and ice-cold ground water continue to defined Yellowstone. This diametrical combination creates the largest collection of active geysers in the world, and Old Faithful geyser is still one of the main draws for the park's four million annual visitors.
     The park rests on top of the world's largest caldera. Just a few miles underground, sections of still-molten rhyolite magma create thousands of hot spots in the Earth's crust. Fortunately for Yellowstone visitors there have been no recent magma eruptions, but the area is shocked every year by frequent earthquakes.
   First reported by John Colter and Jim Bridger in the early 1800s, Yellowstone became America's first national park. Signed into law on March 1, 1872, the parkland was placed into public domain, receiving protection from the Federal Government. A totally new idea at the time, it took decades to develop the details of what a national park should be. Spearheaded by Stephen T. Mather and tireless assistant Horace M. Albright, parks were developed with creature comforts, access roads, trails and an army of park personnel.
   Ongoing studies at Yellowstone include USGS teams from California who take readings and measurements that would indicate any changes in underground activities. A rock's composition, its temperature, confining pressure and water content determine whether it exists as a solid of liquid. These underground conditions create Yellowstone's marvelous sights and sounds, making it the one-of-a-kind tourist destination. Here, the buffalo graze along the Firehole River, never knowing what lies beneath them.

     Park Maps