Yellowstone National Park
Yellowstone National Park has one of the world's largest petrified forests, trees which were long ago buried by ash and soil and transformed from wood to mineral materials. This ash and other volcanic debris are believed to have come from the park area itself as the central part of Yellowstone is the massive caldera of a supervolcano. The park contains 290 waterfalls of at least , the highest being the Lower Falls of the Yellowstone River at .
Yellowstone River
The Yellowstone River Watershed is a river basin spanning across Montana, with minor extensions into Wyoming and North Dakota toward headwaters and terminus, respectively. The Yellowstone Basin Watershed contains a system of rivers, including the Yellowstone River, and four tributary basins: the Clarks Fork Yellowstone, Wind River and Bighorn River, Tongue River, and Powder River. These rivers form tributaries to the Missouri River. The mainstem of the Yellowstone River is more than long. At the headwaters, elevations exceed above sea level and descends to at the confluence with the Missouri River in North Dakota. The watershed spans 34,167 square miles. The area contains many lakes, including Yellowstone Lake. There are no storage dams located on the mainstem of the Yellowstone River. However, the watershed contains five major reservoirs: Bull Lake, Boyson, Buffalo, Bighorn, Tongue River, and Lake De Smet reservoirs.