 Though the Raynolds Expedition was unsuccessful in exploring the region that later became Yellowstone National Park , it was the first federally funded party to enter Jackson Hole and observe the Teton Range . The expedition covered over 2 @,@ 500 miles ( 4 @,@ 000 km ) and explored an area of nearly 250 @,@ 000 square miles ( 650 @,@ 000 km2 ) . In a preliminary report sent east in 1859 , Raynolds stated that the once @-@ abundant bison were being killed for their hides at such an alarming rate that they might soon become extinct . Raynolds 's immediate participation in the American Civil War , followed by a severe illness , delayed him from presenting his report on the expedition until 1868 . Research data and botanical specimens , as well as fossils and geological items that had been collected during the expedition , were sent to the Smithsonian Institution , but were not studied in detail until after the war . Much of the artwork created by Hutton and especially Schönborn was lost , though several of Schönborn 's chromolithographs appeared in Ferdinand V. Hayden 's 1883 report that was submitted after later expeditions . 
