Yellowstone National Park: Black Sand Geyser Basin

Take a tour of multi-colored hot pools and a crater-like geyser on this easy-going, 0.4-mile boardwalk stroll in Yellowstone's Black Sand Geyser Basin.

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Named for the obsidian sand that is common throughout this basin, Black Sand Geyser Basin is home to a plethora of steaming geysers and hot springs. This quick, 0.4-mile boardwalk tour starts at the parking area just west of Old Faithful and heads southwest. In 35 feet, turn right to access an observation deck overlooking Cliff Geyser, a sporadic, crater-like geyser. Next, cross a footbridge over Iron Spring and turn left on the boardwalk that leads to the deep greens of Emerald Pool, one of the park’s most well-known hot springs. Finish off the tour at the aptly-named Rainbow Pool whose multi-colored waters are caused by algae and cyanobacteria.

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-Mapped by Jeff Chow

Black Sand Geyser Basin

Trail Facts

  • Distance: 0.6



Location: 44.4621992, -110.8535153

From the parking area, follow the path to the southwest. In 35 feet, turn right to access the observation deck for Cliff Geyser, a sporadic geyser that resembles a crater.


Location: 44.4618431, -110.8544433

Cross a footbridge over Iron Spring. The ruddy-colored banks of this creek are not caused by iron, but by reddish-brown algae that flourish in these thermal waters. Ahead, turn left onto the boardwalk that leads to the deep greens of Emerald Pool.


Location: 44.4610468, -110.8552587

One of the park’s most well-known hot springs, Emerald Pool’s color is created by the water’s blue reflection and the yellow algae that grows beneath the water’s surface.


Location: 44.4625878, -110.8548483

Examine the various shades of orange around the edges of Rainbow Pool (created by algae and cyanobacteria). Return to Waypoint 1.

Cliff Geyser

Location: 44.4621724, -110.8538479

©Jeff Chow

Iron Creek

Location: 44.4621418, -110.853864

©Jeff Chow


Location: 44.4619006, -110.85388

©Jeff Chow

Emerald Pool

Location: 44.4610448, -110.8552238

©Jeff Chow

Colorful Hot Springs

Location: 44.4621418, -110.8548

©Jeff Chow

Sights at Black Sand Geyser Basin

Location: 44.4622547, -110.8548376

©Jeff Chow

Colorful Pools

Location: 44.4623906, -110.8548832

©Jeff Chow

Views of Cliff Geyser

Location: 44.462494, -110.8548832

©Jeff Chow