From age twelve until age ninety-nine, William Henry Jackson was involved on some level with photography. After a tour of duty in the Civil War, he headed West and eventually settled in Omaha, Nebraska, where he opened a portrait photography studio with his brother Edward. As Jackson explained, however, “Portrait photography never had any charms for me, so I sought my subjects from the house-tops, and finally from the hill-tops and about the surrounding country; the taste strengthening as my successes became greater in proportion to the failures.” In 1870 he accompanied geologist Ferdinand Vandiveer Hayden on an expedition across Wyoming, along the Green River, and eventually into the Yellowstone Lake area. Jackson’s images were the first published photographs of Yellowstone. Partly on the strength of these photographs, the area became America’s 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 finally settled in Denver, Colorado, where he worked as a commercial landscape photographer and continued to publish his photographs as postcards. 
FROM http://www.getty.edu/art/collection/artists/1853/william-henry-jackson-american-1843-1942/

http://www.iphf.org/hall-of-fame/william-henry-jackson/