William Henry Jackson (1843-1942) was born in Keesville, NY and took up photography after serving during the Civil War. Throughout his career, he created iconic photographs of the natural landscapes of the Western U.S., especially in the Rocky Mountain and Yellowstone areas. In 1870 he accompanied geologist Ferdinand Vandiveer Hayden on an expedition across Wyoming, along the Green River, and eventually into the Yellowstone Lake area. He brought images of these landscapes to the public, and his photographs of Yellowstone helped convince the U.S. Congress to make it the first national park in March 1872. On one of several independent expeditions that he headed, Jackson also became the first to photograph the prehistoric Native American dwellings in Mesa Verde, Colorado. He settled in Denver, Colorado, establishing a photography studio. Today, his photographs are in many important galleries and museums, with the Denver Public Library holding over 3,000 works.