Welcome to West Thumb Geyser Basin! Yellowstone has 11 such basins but West Thumb has something special: a lakeside view! We’ll get to walk along Yellowstone Lake as we explore this basin.

Note: This tour is 0.6 miles long and covers all the essentials of West Thumb in 1-2 hours.

10 minutes • Admission Ticket Not Included

On our right is the Surging Spring. It’s a hot spring that’s 28 feet deep. Can you see the steam coming off it? This pool simmers at 193 degrees Fahrenheit. For context, an extra hot cup of coffee is about 185 degrees!

10 minutes • Admission Ticket Free

A little ahead and to our left, we’ll see another hot spring called the Collapsing Pool. But does it collapse? Well, it did once! In 1959, part of that mineral build-up around the edges of this pool collapsed in an earthquake. The unflattering nickname has stuck ever since. Ouch!

10 minutes • Admission Ticket Free

That colorful pool on our left is the Thumb Geyser. And it has bacteria to thank for its vibrant appearance! In the mid-1970s, this whole Geyser Basin started becoming less active. The geysers here weren’t erupting as much and the hot springs weren’t quite as hot. Scientists couldn’t explain it. Maybe the pools underground weren’t refilling with rainwater as quickly as they used to? Maybe debris or changes in the rock made it so they heated less intensely? To this day, no one has a concrete answer. But whatever the reason, it’s been good news for the bacteria around here!

10 minutes • Admission Ticket Free

This hot spring used to be about 18 feet across with temperatures between 172 and 182 degrees. But in the last 30 years, it has cooled and drained. Where did that water go? Well not too far actually — to The Abyss Pool! We’ll see that pool shortly.

10 minutes • Admission Ticket Free

To our right sits Twin Geyser. Let’s look a little closer. Can you see the two vents? That’s where it gets its name! Twin has been known to spit water up 120 feet into the air. The water comes out both vents, but converges to create a single magnificent spray! Unfortunately, it hasn’t erupted since 1999. But that doesn’t mean that won’t change!

10 minutes • Admission Ticket Free

Hillside Geyser is off to our right. It used to spit water 70 feet into the air every day! But it hasn’t done that since 2006, possibly due to human interference. Scientists’ philosophy is to do no harm, but visitors here have never had the same perspective. In the 1800s, the army even used Old Faithful to clean their dirty clothes!

10 minutes • Admission Ticket Free

Pause here. On our left is Abyss Pool. Feel free to walk to the observation deck to our left for a better look! This hot spring is 53 feet deep, making it one of Yellowstone’s deepest hot springs! Hence the name, of course.

10 minutes • Admission Ticket Free

The pool directly to our right is called Black Pool. You’ll probably notice that it’s not black; it’s a beautiful blue! What happened there? Well, before the 1990s, this pool clocked in at around 132 degrees Fahrenheit. That’s really not that hot, and allows for much darker-colored bacteria to thrive. The dark bacteria combined with the depth of this pool at 30 feet made the water look black!

10 minutes • Admission Ticket Free

On our left stands the Big Cone Geyser. You can’t miss it! This is the largest geyser in West Thumb, measuring 23 feet in diameter. Its vent is around 30 inches wide. But this geyser is no Old Faithful. Big Cone erupts very rarely, and when it does, it throws water only about a foot into the air. I guess size isn’t everything!
On our left stands the Big Cone Geyser. You can’t miss it! This is the largest geyser in West Thumb, measuring 23 feet in diameter. Its vent is around 30 inches wide. But this geyser is no Old Faithful. Big Cone erupts very rarely, and when it does, it throws water only about a foot into the air. I guess size isn’t everything!

10 minutes • Admission Ticket Free

To our left is none other than Fishing Cone Geyser. Sometimes it’s submerged under lake water, so look closely. In the mid-1800s, European settlers and explorers used to come out here to fish for their dinners. They’d stand near Fishing Cone with their rods and reels and wait. Something would bite! A trout! The men would reel the fish in, holding steady against the thrashing. But did they bring the fish up to the shore and let it flop around? Of course not! They’d lift their rod right over the Fishing Cone and dip the floppy fish right in. Within minutes, the trout was still and lifeless… and cooked to perfection!

5 minutes • Admission Ticket Free

This next geyser on our left is a little harder to spot if you’re visiting in the spring. It’s called Lakeshore Geyser, and it has two vents pretty close to each other. If you’re here in late summer, you’ll probably see them steaming right at the shore. If not, look for two vents right below the water’s surface.

5 minutes • Admission Ticket Free

Yellowstone Lake covers 136 square miles and sits at 7,732 feet above sea level, making it one of the country’s largest high-elevation lakes. Its average depth is around 139 feet, but its deepest point is around 400 feet.

5 minutes • Admission Ticket Free

The linked pools on our right used to be known simply as the Blue Pools. Today, the closer one is Bluebell Pool and the farther one is Seismograph Pool. What changed? Well, a small earthquake hit!

5 minutes • Admission Ticket Free