Solitary Geyser

A geyser erupts water on a winter day, coating the nearby pine trees with ice.
Winter eruption of Solitary Geyser.

Quick Facts
Old Faithful

Solitary Geyser exists on a short trail up the hillside away from the majority of the concentrated geysers in the Old Faithful area. An active geyser since the early years of the park, Solitary Geyser is a clear, blue pool with a geyserite rim. Shallow sinter shelves around the main pool are filled with orange and yellow thermophiles that continue along the runoff channels. Rims of geyserite line the runoff channels as well. Eruption intervals are in the 4–8 minute range.

Solitary Geyser has an average temperate of 182.8°F (83.8°C), an average pH of 6.7, and an average conductivity of 1790 uS/cm.


Geysers have constrictions in their plumbing systems that prevent water from moving freely to the surface where heat would escape. Water beneath the constrictions creates a buildup of steam. Eventually the steam pushes water past the constrictions and the geyser erupts.

Upper Geyser Basin

The majority of world’s active geysers are in the Upper Geyser Basin, including Old Faithful. Only four other places in the world have large concentrations of hydrothermal features: Russia (Kamchatka), Chile, New Zealand, and Iceland.

The heat for the hydrothermal features comes from Yellowstone’s volcano. Molten rock or magma may be as close as 3-8 miles (5-13 km) underground. Rain and snow supply water that seeps down several thousand feet (more than a kilometer) below the surface where it is heated.

Underground cracks form a natural plumbing system. Hot water rises through the plumbing to produce hot springs and geysers.

Use Caution in Hydrothermal Areas

  • Stay on boardwalks and designated trails.
  • Hydrothermal water can severely burn you.
  • Never run, push, or shove.
  • Supervise children at all times.
  • Do not scratch hydrothermal mats.

You are responsible for your safety.

Think safety, act safely. Yellowstone is a dangerous place.

Yellowstone National Park

Last updated: April 5, 2024