Abyss Pool is a hot spring in Yellowstone National Park’s West Thumb Geyser Basin in Teton County, Wyoming, noted for its clear blue water, striking appearance, and unusual depth. Chief Park Naturalist Clyde M. Bauer gave it its name, possibly inspired by Lieutenant G. C. Doane’s 1870 account of “deep abysses” visible beneath a nearby spring’s surface. Visitors admired its beauty as early as 1883. At 53 feet, or 16 meters, deep, it is one of the basin’s distinctive thermal features. Though usually non-eruptive, it briefly erupted like a geyser between 1987 and 1992 before returning to its normal state.