The early human history of Yellowstone is gathered from the clues and remains of a lifestyle without a system to leave a written record. We do know that people hunted the area now called Yellowstone as long ago as 11,000 years and have lived there off and on for much of the last 8,500 years. These prehistoric peoples were mostly hunter-gatherers who may also have practiced crude agricultural practices. What we know of them has been deduced mostly from pottery and tool remains that have been found in various areas throughout Yellowstone National Park.

When the first white explorers entered Yellowstone they found groups of people they named Sheepeaters, Native Americans who survived by hunting bighorn sheep and fishing the headwaters of the Snake, Madison, and Yellowstone Rivers. Other tribes would have passed through on their way back and forth from promising hunting grounds. Small encampments of Sheepeater Shoshone remained in Yellowstone National Park until 1871, when they were moved to the Shoshone Wind River Reservation in central Wyoming.

The first known white man to enter Yellowstone was a member of the Lewis and Clark expedition by the name of John Colter. He spent the winter of 1807-08 traveling, trapping, and exploring Yellowstone, moving down into Jackson Hole and crossing the Tetons into Idaho. When he returned from his adventures people mocked his stories of steam rising from the earth as mad hallucinations, earning Yellowstone its first name as "Colter’s Hell".

During the era of the beaver trade (1820s – 1840) and after the Civil War when mineral prospectors first entered the area, similar wild tales of Yellowstone continued to be told, no doubt combining rumor with direct observation. Truth and fiction were so entangled that it was only after local Montana rancher Nathaniel P. Langford set out with local leaders that the truth of the stories came to be accepted.

In 1871, the federal government got involved when it commissioned Dr. Ferdinand V. Hayden to take a scientific survey of the country. In his troop were artist Thomas Moran and landscape photographer William Henry Jackson. The scientific results combined with the stunning imagery captured in Moran’s art and Jackson’s photography showed the American people that Yellowstone was a place like no other. On March 1, 1872, Congress voted to set aside 2.2 million acres as Yellowstone National Park, named after the sulfurous yellow rocks seen below the falls of the Yellowstone Grand Canyon and throughout the park.