Thomas Moran created this field sketch, one of many, while documenting the thermal features and other natural wonders of the Yellowstone region as part of the first federally funded expedition into the area. The expedition was sponsored by the U.S. Geological Survey (USGS) and led by geologist Ferdinand V. Hayden. Hayden realized the importance of having artists and photographers accompany the group in order to document the area's features. Moran, hired by the Northern Pacific Railroad, was not the expedition's official artist (this title belonged to Henry Wood Elliott). However, Moran's sketches were the only ones executed in color and concisely captured the complex features. His sketches, along with the photographs of USGS photographer William Henry Jackson, were exhibited to Congress, leading to the creation of the world's first national park. Since Yellowstone National Park was set aside because of its geothermal wonders, this sketch of what is now known as Grand Prismatic Spring in the Midway Geyser Basin, was integral to the park's designation.