1. Yellowstone is bigger than two U.S. states.
At 3,472 square miles—over 2.2 million acres—Yellowstone is larger than the states of Rhode Island and Delaware combined. The vast majority of its territory is situated in Wyoming, but it also creeps into neighboring Montana and Idaho. Though not the largest of the United States’ national parks, it is noteworthy for its dense concentration of geysers, mudpots, steam vents and hot springs. According to UNESCO, which has designated Yellowstone a World Heritage Site, half of all the known geothermal features on the globe are nestled within the park.
WATCH: How the Earth Was Made: Yellowstone on HISTORY Vault
2. A veteran of the Lewis and Clark expedition may have been the first American to see Yellowstone.
While there is evidence of human habitation in Yellowstone dating back more than 10,000 years, its geographical wonders were completely unknown to Americans until the 19th century. The site’s first non-Indian visitor was most likely John Colter, a former member of Lewis and Clark’s Corps of Discovery expedition who had embarked on a career as a fur trapper and mountain man. In the winter of 1807-08, he made a solo journey into the Yellowstone region and supposedly returned with stories of its canyons, waterfalls and gurgling hot springs. A nearby area even became known as “Colter’s Hell” after his seemingly unbelievable descriptions of its geothermal activity. While historians still debate the extent of Colter’s travels, many now believe he was the first white man to lay eyes on what later became Yellowstone National Park.
3. One of Yellowstone’s earliest explorers was stranded there for 37 days.
Miners and fur trappers occasionally ventured into Yellowstone in the years after John Colter’s visit, but the first organized surveys didn’t begin until the late 19th century. During one of these excursions in 1870, a Montana bureaucrat named Truman Everts became separated from his party and was eventually given up for dead. After losing his horse and most of his supplies, the 54-year-old spent over a month surviving on thistle and enduring snowstorms, delirium and a painful scalding from a hot spring. By the time he was finally found alive in October 1870, he weighed just 90 pounds and was suffering from frostbite so severe that it had worn his feet to the bone. Everts’ rescuers described him as looking like “nothing but a shadow,” but he eventually recovered and even wrote an account of his ordeal titled “Thirty-Seven Days of Peril.” His amazing tale of survival has since been credited with helping publicize the movement to make Yellowstone a national park.
4. The park sits atop the largest supervolcano in North America.
Early accounts of Yellowstone’s geysers, hot springs and fumaroles were often dismissed as frontier legends, but scientists now know that they are the result of a “supervolcano” located beneath the park. The system is still considered active and contains a reservoir of magma big enough fill the Grand Canyon several times over. While scientists are not concerned about an eruption occurring any time soon—the last was some 640,000 years ago—the volcano is powerful enough to potentially shroud much of the continental United States in ash.
5. A painter played a crucial role in Yellowstone’s creation.
A key chapter in Yellowstone’s development came in the summer of 1871, when geologist Ferdinand Hayden led the first federally funded expedition to the region. Along with botanists and zoologists, Hayden’s team also included a photographer and a young artist named Thomas Moran, who produced more than 30 sketches and watercolors of Yellowstone’s cliffs, geysers and rivers. Combined with the photographs, Moran’s artworks offered Americans their first glimpse of the area’s natural beauty. When the paintings were later exhibited in Congress, they helped win many politicians over to the idea of making Yellowstone a “national playground.” On February 27, 1872, the House of Representatives voted 115 to 65 in favor setting the region aside as America’s first national park. President Ulysses S. Grant signed the bill into law just two days later.
6. Yellowstone was originally nicknamed 'Wonderland.'
Yellowstone’s remote location ensure that it only received a couple thousand visitors during its first several years as a national park, but tourism later exploded following the 1883 completion of the Northern Pacific Railroad. Capitalizing on the popularity of Lewis Carroll’s book Alice’s Adventures in Wonderland, the Northern Pacific launched an ad campaign that presented the park as America’s “New Wonderland.” One 1885 pamphlet even included a fictional endorsement from Alice herself, who offered breathless descriptions of Yellowstone’s geography. “The Park, let me tell you, is an extensive area literally crowded with natural curiosities of the most wonderful character,” the character gushed. “Tell me, is this not Wonderland?”
7. The U.S. Army ran the park for over 30 years.
During its early years, Yellowstone suffered due to meager government funding and a series of ineffective superintendents. Tourists vandalized the park’s geysers and rock formations, and poachers and private interests hunted its wild game and harvested its timber. The damage was only slowed in 1886, when a U.S. Army cavalry company was dispatched to administer Yellowstone and stand guard over its natural treasures. The troops immediately went to work expelling squatters, rounding up poachers and enforcing regulations, and by 1894 their successes had encouraged Congress to pass a new law protecting the park’s wildlife. Army forces would remain the wardens of Yellowstone until 1918, when they handed the reigns to the newly created National Parks Service.
8. Yellowstone includes the nation's oldest herd of bison.
According to the National Park Service, Yellowstone is the only place in the United States where buffalo have continuously roamed since the prehistoric era. The park’s herd dwindled to just 23 animals during the late 19th century, when overhunting helped drive the bison to the brink of extinction, but the population later bounced back thanks to more effective stewardship and protection. The roughly 5,500 bison that live in Yellowstone today constitute the nation’s largest and oldest free-range herd.
9. The park once featured a 'bear lunch counter.'
For much of its history, Yellowstone had open-air garbage dumps on park grounds. The trash heaps may have been an eyesore, but since they attracted scavenging animals, they also became a popular location for catching black bears and grizzlies in the midst of a feeding frenzy. In the 1920s and 30s, park operators even installed bleachers for tourists and posted signs over the trash pits that read “Lunch Counter—For Bears Only.” The dumps were eventually closed to the public during World War II, but not before several tourists had been injured in bear attacks.
10. Old Faithful is not as faithful as it once was.
Of all of Yellowstone’s geysers, none is more iconic than “Old Faithful,” which is capable of spewing water 180 feet into the air. The geyser first earned its name in 1870, when a group of early explorers noted that it erupted roughly once every 60 minutes. Early park promoters even advertised Old Faithful as erupting “every hour on the hour,” but decades of earthquakes—including one in 1959 that measured 7.5 on the Richter scale—have since altered its network of underground fissures and caused it to slow down. These days, the gusher often takes breaks as long as 90 minutes between eruptions.