Midway Geyser Basin – 4 Geothermal Landmarks in Yellowstone

Yellowstone National Park is a land of wonders, and Midway Geyser Basin is one of its most magical spots.

It's home to 4 distinct geothermal landmarks, including the famous Grand Prismatic Spring, Excelsior Geyser Crater, Turquoise Pool, and Opal Pool.

If you've ever dreamed of seeing a rainbow in liquid form, this is the place to go. But don't just take my word for it and see for yourself.

Let's dive into what makes this place so unique.

What Makes Midway Geyser Basin Special?

Midway Geyser Basin is a small area, but the features here are gigantic and unforgettable.

It's also known as "Hell's Half Acre," a nickname given by writer Rudyard Kipling in the 1800s.

But don't worry because it's more heavenly than hellish. Here is a brief description of all 4 unique landmarks of the basin.

Grand Prismatic Spring: A Rainbow in Liquid Form

The Grand Prismatic Spring is the largest hot spring in North America and the third-largest in the world.

It measures an incredible 370 feet (113 m) across and 121 feet (37 m) deep, making it larger than a football field and deeper than a 10-story building.

The spring pours out 560 gallons (2,120 liters) of water per minute into the Firehole River, with temperatures ranging from 147°F to 188°F (64°C to 87°C). Its vivid rainbow colors are created by thermophilic microorganisms that thrive at different water temperatures.

Learn more about the largest hot spring in North America

Excelsior Geyser Crater: A Giant of the Past

Once the largest geyser in the world, the Excelsior Geyser Crater is now a massive, steaming hot spring.

The crater itself is enormous, measuring 276 feet (84 m) by 328 feet (100 m), it is nearly the size of a football field. The water in Excelsior reaches a scorching 199°F (93°C) and churns constantly, releasing thick clouds of steam into the air.

Today, it discharges 4,050 gallons (15,340 liters) of boiling water per minute into the Firehole River, making it the park's most productive hot spring.

In the 1880s, Excelsior erupted with incredible force, spewing water as high as 300 feet (91 m) into the air. These violent eruptions damaged the geyser's internal structure, causing it to go dormant for nearly a century.

It briefly came back to life in 1985, erupting for two days with bursts reaching 20 to 80 feet (6 to 24 m).

Since then, it has remained a hot spring, its turbulent waters constantly bubbling and boiling within the crater.

Turquoise Pool: A Gem-Like Spring

The Turquoise Pool is 100 feet (30 m) by 110 feet (34 m) and stands out for its tranquil, gem-like appearance. The pool's milky white bottom, combined with its vivid blue-green water, creates an opalescent glow that makes it one of the most beautiful features in Midway Geyser Basin.

The spring's water temperature ranges from 142°F to 160°F (61°C to 71°C), and while it appears calm on the surface, it's an active geothermal feature.

Unlike many other springs, Turquoise Pool has no visible overflow channel; instead, its water drains through seepage into the ground. It is also connected to the nearby Excelsior Geyser Crater through underground channels.

When Excelsior was active in the past, Turquoise Pool's water levels dropped by as much as 10 feet, taking nearly a year to recover. The area around the pool is often barren, but in June and July, the purple-fringed gentians bloom, adding lovely pops of color to the landscape.

Opal Pool: A Shimmering Beauty

The Opal Pool has opalescent colors that shift with changing light and geothermal activity. Although smaller than Grand Prismatic Spring and Excelsior Geyser, Opal Pool is equally fascinating.

Its exact size and depth vary depending on water levels, which can dramatically change over time. In fact, the pool is known to sometimes drain completely, leaving behind a dry, crater-like depression, only to refill over months.

The pool's water temperature is cooler than some of the larger springs, so colorful microorganisms and mineral deposits thrive along its edges. These microbes create colorful patterns and hues, making the pool appear as though it's glowing.

The pool is surrounded by delicate mineral formations, adding to its unique beauty.

What's It Like to Visit?

Visiting Midway Geyser Basin is an experience for all your senses. The air smells like sulfur (it's not bad, just part of the adventure). Steam rises constantly from the springs, and if you visit on a cool day, it can feel like you're walking through a magical mist.

The boardwalks take you right up close to the features, so you can see the incredible colors and bubbling waters.

But here's the catch: It's hard to capture it all in a photo. The Grand Prismatic Spring is so huge that you can't see the full rainbow effect from ground level.

If you're up for a little hike, though, there's a solution! You can climb a hill near the Fairy Falls Trail for a bird's-eye view. It's worth the effort.

The boardwalk is a short, wheelchair-accessible loop that takes you past all the major features. You'll want to stop and stare at every single one.

Safety First

Yellowstone is breathtaking, but it's also dangerous if you're not careful. Stay on the boardwalks at all times because the ground here is unstable, and the water is scalding hot.

Keep an eye on kids and dogs, and don't throw anything into the springs (even coins). These features are fragile and take thousands of years to form.

When Should You Visit?

While Yellowstone is open year-round, the best time to visit Midway Geyser Basin is spring, summer, or fall. In winter, you'll need a guided snowmobile or snow coach tour to get here. No matter when you visit, you'll want to bring:

• Comfortable walking shoes
• A camera (or your phone)
• Water, sunscreen, and a hat