//
Permits are required for fishing, and not all areas are open to fishing; check with rangers. Native species include arctic grayling, Westslope cutthroat trout and Yellowstone cutthroat trout. Non-native species include brook trout, brown trout, lake trout and rainbow trout. Check the park's fishing guidelines for the latest rules and regulations.
With a surface area of 132 mi2, Yellowstone Lake is the largest lake at high elevation (more than 7,000 ft) in North America. It is a natural lake, situated at 7,733 ft above sea level. It is roughly 20 mi long and 15 mi wide with 141 mi of shoreline. It is frozen nearly half the year. It freezes in late December or early January and thaws in late May or early June.
This rock formation is accessible via an easy one-mile (1 mi) walk, and there is also a bicycle trail leading to the bridge. The Natural Bridge was formed by erosion of a rhyolite outcrop by Bridge Creek. The top of the bridge is approximately 51 ft above the creek. A short switchback trail leads to the top, though travel across the bridge is now prohibited to protect this feature.
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.
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 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.
The original bridge was built in 1902 as a rough-hewn corduroy log bridge with a slightly different alignment than the current bridge. The existing bridge was built in 1937. The Fishing Bridge was historically a tremendously popular place to fish. Angling from the bridge was quite good, due to the fact that it was a major spawning area for cutthroat trout. However, because of the decline of the cutthroat population (in part, a result of this practice), the bridge was closed to fishing in 1973. Since that time, it has become a popular place to observe fish.