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Photo: J. Schmidt, Public domain via Wikimedia Commons
Hayden Valley is one of the best places in the park to view a wide variety of wildlife. It is an excellent place to look for grizzly bears, particularly in the spring and early summer when they may be preying upon newborn bison and elk calves. Large herds of bison may be viewed in the spring, early summer, and during the fall rut, which usually begins late July to early August. Coyotes can almost always be seen in the valley. Bird life is abundant in and along the river. A variety of shore birds may be seen in the mud flats at Alum Creek. A pair of sandhill cranes usually nests at the south end of the valley. Ducks, geese, and American white pelicans cruise the river. The valley is also an excellent place to look for bald eagles and northern harriers.
Hayden Valley is a large, sub-alpine valley within Yellowstone National Park straddling the Yellowstone River between Yellowstone Falls and Yellowstone Lake. The valley floor along the river is an ancient lake bed from a time when Yellowstone Lake was much larger.
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The Sulphur Caldron area can be viewed from a staging area just north of Mud Volcano. The yellow, turbulent splashing waters of the Sulphur Caldron are among the most acidic in the park with a pH of 1.3. Other features which can be viewed from this overlook are Turbulent Pool (which is no longer "turbulent") and the crater of a large, active mud pot.
This was once a hilltop thermal feature that would hurl mud into the nearby trees during eruptions, but a particularly large eruption blew apart the Mud Volcano, leaving a hot, bubbling mud pool at the base of the hill. Access to the area is via a short loop from the parking lot past the Dragon's Mouth and the Mud Volcano that is handicapped accessible, and a half-mile (0.5 mi) upper loop trail via Sour Lake and the Black Dragon's Caldron that is relatively steep. The rhythmic belching of steam and the flashing tongue of water give the Dragon's Mouth Spring its name, though its activity has decreased notably since December 1994. The Black Dragon's Caldron exploded onto the landscape in 1948, blowing trees out by their roots and covering the surrounding forest with mud. In January 1995, a new feature on the south bank of Mud Geyser became extremely active, covering an area of 20 x and comprised of fumaroles, small pools, and frying-pan type features. The most dramatic features of the Mud Volcano area, including the huge seething mud pot known as the "Gumper", are open to the public only via off-boardwalk ranger-guided walks.
The LeHardy Rapids are a cascade on the Yellowstone River. Geomorphologically, it is thought that this is the actual spot where the lake ends and the river continues its northward flow. In the spring, many cut-throat trout may be seen here, resting in the shallow pools before expending bursts of energy to leap up the rapids on their way to spawn under Fishing Bridge. A boardwalk, built in 1984, provides access to the area, although it is closed during the spring nesting season to protect this sensitive bird habitat.
The Grand Canyon of the Yellowstone is the primary geologic feature in the Canyon District. It is roughly 20 mi long, measured from the Upper Falls to the Tower Fall area. Depth is 800 to; width is 1500 to. The present canyon is no more than 10,000 to 14,000 years old, although there has probably been a canyon in this location for a much longer period. Chemical processes over time have left stripes and patches of different colors in the rock of this canyon. Trails lead along the north and south rims of the canyon, but while traveling the entire trail in one day is possible, it makes for a long and tiring day. Best to make it two shorter (~3 hour) day hikes. If you're a photo buff, plan your walks so the sun illuminates the opposite side for great pictures.
The Upper Falls is 109 ft high and can be seen from the Brink of the Upper Falls Trail and from Uncle Tom's Trail. The Lower Falls is 308 ft and can be seen from Lookout Point, Red Rock Point, Artist Point, Brink of the Lower Falls Trail, and from various points on the South Rim Trail. The Lower Falls is often described as being more than twice the size of Niagara, although this only refers to its height and not the volume of water flowing over it. A third falls can be found in the canyon between the Upper and Lower falls. Crystal Falls is the outfall of Cascade Creek into the canyon. It can be seen from the South Rim Trail just east of the Uncle Tom's area.
The Canyon Village complex is part of the Mission 66 project in the park. The Visitor Center was completed in 1957, and the new lodge was open for business in the same year. Though some people consider the development representative of the architecture of the time, none of the present buildings in the complex can be considered historic. There are, however, still remnants of the old hotel, lodge, and related facilities.