Grand Prismatic Hot Spring

The Grand Prismatic Spring is an essential trail to check out on your visit to Yellowstone National Park. This trail gets extremely busy, especially in the summer at the height of tourist season. We suggest heading out on this hike early in the morning to beat the crowds. Alternatively, you can check out this trail in the evening when most folks have cleared out for the night. The trail to the Grand Prismatic Spring is a wide, gravel path with a low incline. This route is accessible for most folks, including people who use wheelchairs or folks pushing strollers.

The Grand Prismatic Spring is truly a sight to behold. This natural feature’s vivid coloration and immense size will leave you speechless. Spanning approximately 370ft in diameter and rimmed with vivid shades of red, orange, green, and blue, it’s hard to fathom that the Grand Prismatic Spring is even real. But, no matter your age or skill level, the hike up to this otherworldly formation is definitely a must-do on your visit to Yellowstone National Park.

To hike to the Grand Prismatic Spring, begin at the Fairy Falls Trailhead and follow the path west over the Firehole River and along Fountain Flat Drive for approximately 0.8mi to the Grand Prismatic Spring Overlook.

Enjoy the incredible views, and be sure to snap some pictures of this awe-inspiring feature. When you are ready to head home, simply retrace your steps back to the Fairy Falls Trailhead, where you began.

Trail Highlights

The Grand Prismatic Spring

The Grand Prismatic Spring is the largest natural hot spring in the United States of America and the third largest hot spring in the World. With a diameter of approximately 370ft and a depth of approximately 160ft, this spring is well known for its vivid, prismatic colors. The spectacular rainbow of color that gives this spring its name is caused by microbial mats: multi-layered sheets of microorganisms, largely bacteria, on the edges of the water. These microorganisms make the shoreline of the spring bright red, orange, yellow, and green.

In the summertime, these mats are usually shades of red and orange, and in the winter, they shift to the cooler greens and blues. With an average temperature of 160 degrees Fahrenheit (70 C), you cannot enter or go near the spring; the high acidity of the water combined with the scalding temperature would be instantly fatal to anyone who tried. The Grand Prismatic Spring is truly an otherworldly sight and well worth a stop on your visit to Yellowstone National Park.

Frequently Asked Questions

Can you swim in the Grand Prismatic Spring?

No. Absolutely not. You cannot swim in the Grand Prismatic Spring. The high temperatures and high acidity of the water would be instantly fatal to anyone who entered the Grand Prismatic Spring.

Why is the Grand Prismatic Spring so colorful?

The vivid colors of the Grand Prismatic Spring are caused by microbes on the water’s edge.