Norris Geyser Basin, named for the park’s second superintendent, is one of the most intriguing places in Yellowstone. It’s rich in history, the site of a National Historic Landmark, one of the park’s original trailside museums. The Norris Geyser Basin Museum isn’t the only old thing around Norris. Norris is home to ancient hydrothermal features—some hot springs may be 115,000 years old, possibly the oldest springs in the park!

But what makes Norris Geyser Basin so captivating is that the features here are some of the hottest and most acidic around. You will smell the odor of sulfur as you approach and through the steam you will find hissing fumeroles, splashing geysers and beautiful clear pools as well as murky, muddy, cloudy ones. Minerals and microbes decorate the features with brilliant colors of orange, yellow, rust and green.

At Norris you’ll find Steamboat Geyser, the tallest geyser in the world, which during major eruptions, blows water and steam 300 feet into the air with a thundering roar. Norris is also home Echinus geyser, the largest acidic geyser in the world. Acid geysers are rare and Norris boasts more than anywhere else on earth.

Hottest, oldest, most acidic…Norris is full of superlatives. But the caption under the geyser basin’s photo should read “Most Likely to Change.” Norris is one of the most dynamic places in the park with features changing constantly. Situated along two faults and the ring fractures of the most recent caldera, the excessive seismic activity at Norris contributes to quick dramatic changes in temperature, color, water level, pH, and activity of the features here. Sometimes overnight new features form, dormant geysers begin to erupt, hot springs turn into geysers or fumeroles.

As you experience the sights, sounds and smells of Norris by walking two miles through the basin, be careful to stay on the boardwalks and trails as this is one of the most dangerously hot, acidic areas in the park with features constantly changing. Join a ranger-led walk in the summer months to learn the latest fascinating findings. Return often, as it is always different.