Thomas Moran (February 12, 1837 - August 25, 1926) was an artist of the Hudson River School. Thomas Moran's vision of the Western landscape was critical to the creation of Yellowstone National Park. His pencil and watercolor field sketches and paintings captured the grandeur and documented the extraordinary terrain and natural features of the Yellowstone region.

Moran's artwork was presented to members of Congress by park proponents. These powerful images of Yellowstone fired the imagination and helped inspire Congress to establish the National Park System in 1916.

-Wikipedia