This list summarizes the major expeditions to the Yellowstone region that led to the creation of the park and contributed to the protection of the park and its resources between 1869 and 1890. When President Ulysses S. Grant created Yellowstone National Park with the signing of the Act of Dedication, March 1, 1872, it was the result of three major expeditions into the region, expeditions that brought the wonders of Yellowstone into public view. Prior to 1869, the Yellowstone region—its rivers, waterfalls, lakes, mountains, valleys and geothermal features were essentially part of an unknown and unexplored territory. Even after the creation of the park, the region remained largely unexplored and its resources unprotected for over a decade until the U.S. Army assumed management of the park in