It was during this tour that Hancock had the opportunity to contribute to the creation of Yellowstone National Park. In August 1870, he ordered the 2nd Cavalry at Fort Ellis to provide a military escort for General Henry D. Washburn's planned exploration of the Yellowstone Region. The expedition, which was a major impetus in creating the park, became known as the Washburn-Langford-Doane Expedition. Hancock's order led to the assignment of Lt. Gustavus Cheyney Doane and a troop of 5 cavalrymen from Fort Ellis to escort the expedition. In 1871, Captain John W. Barlow during his exploration of the Yellowstone region formally named a summit on what would become the southern boundary of the park Mount Hancock to honor the general's decision to provide the escort.