Abyss Pool

Overview

Abyss Pool is a vividly blue, deceptively deep hot spring on the West Thumb Geyser Basin boardwalk along the shore of Yellowstone Lake. At roughly 53 feet deep, it looks bottomless and photographs beautifully from the railings—this one is all about color, clarity, and mood.

What You'll See

• A steep-sided, glassy pool that shifts from cobalt to turquoise, with subtle thermal colors near the rim.
• The pool is typically quiet, but it has a history of rare, powerful outbursts; in recent seasons its water warmed and the blue deepened. Come for the serene, color-drenched scene, not eruptions.

Geology & History

West Thumb sits within a smaller caldera nested inside the greater Yellowstone Caldera. Most features here are alkaline-chloride springs: rain and snowmelt circulate deep underground, heat up, and return carrying dissolved gases and minerals, gradually dissolving cone-like cavities that become these deep pools. Abyss Pool was named for its impressive depth, and 19th-century surveyors famously raved about peering into its “abysses.”

Wildlife & Setting

The lakeside setting draws water birds, and bison can wander the nearby roads. Just offshore, low-temperature vents on the lakebed support aquatic life, including native cutthroat trout.

Safety & Etiquette

Stay on the boardwalks and keep kids close. Hydrothermal ground can be thin, the water can severely burn, and tossing objects into features damages them and can alter their behavior.

Best Time to Visit

Early morning or late day brings softer light that makes the blues pop and, often, calmer steam so the view stays clear. Pair this stop with nearby Black Pool and the rest of the compact West Thumb loop for a high-reward, short walk.