Leather Pool

Leather Pool is a fascinating and historically dynamic hot spring located in the Lower Geyser Basin of Yellowstone National Park. Known for its distinctive coloring and shifting geothermal behavior, the pool has undergone significant transformations over the last century, reflecting the ever-changing nature of Yellowstone’s volcanic environment. 

It earned its memorable name from the thick mat of brown, leather-like thermophilic bacteria that once thrived along its edges, forming a textured surface that visitors likened to tanned hide. This biological layer added both visual interest and scientific value, revealing how microscopic life adapts to extreme environments.

Leather Pool

Quick Reference: Leather Pool

Feature	Details
Location	Lower Geyser Basin, Yellowstone National Park
Thermal Type	Hot Spring
Average Temperature	139.3°F (59.6°C)
Color & Appearance	Brown, leather-like texture from thermophilic bacteria
Notable Activity	Temperature spike and eruption after 1959 Hebgen Lake Earthquake; later cooled
pH Level	6.9
Average Conductivity	1600 uS/cm
Accessibility	Located along boardwalk viewing areas in Lower Geyser Basin
Best Time to Visit	Year-round, but safest when boardwalks are clear of winter ice

Prior to 1959, Leather Pool was a warm pool with an average temperature of about 139.3°F (59.6°C), making it suitable for heat-loving bacterial communities that produced its characteristic brown color. However, everything changed dramatically after the 1959 Hebgen Lake Earthquake—one of the most powerful seismic events in Yellowstone’s recorded history. The underground plumbing system feeding Leather Pool was altered, causing water temperatures to spike sharply. The sudden extreme heat killed the bacteria that had covered the pool’s surface, stripping it of its signature appearance. During this period, Leather Pool was observed to erupt, behaving briefly like a geyser due to increased underground pressure and heat.

Over time, as hydrothermal conditions gradually stabilized, Leather Pool began to cool again. With temperatures eventually returning to more moderate levels, the brown thermophiles recolonized the pool, restoring its original leather-like texture and appearance. Today, the pool once again teems with microbial life, serving as a reminder of Yellowstone’s dynamic and unpredictable geothermal forces. Leather Pool typically maintains an average pH of 6.9, charting close to neutral, and an average conductivity of about 1600 uS/cm, indicating a moderate concentration of dissolved minerals in its waters.

Visitors to the Lower Geyser Basin are often drawn to Leather Pool not only for its unusual appearance but also for the story it tells about the intersection of geology and biology. It stands quietly beside nearby geysers and springs, yet its history represents the powerful forces constantly transforming Yellowstone from beneath the surface. Leather Pool remains an outstanding example of how drastic environmental change can alter — and then restore — life in extreme ecosystems.