The boiling river is one of the best not-so-well-kept secrets of Yellowstone. It’s becoming increasingly popular, but isn’t as widely know about as some of the other world-famous attractions in the park. If you’re in the Mammoth Hot Spring area, it’s well worth a stop just to wade around in even if you don’t have a swimsuit with you. The only way we found out about it was because our Gaperguide mentioned it when we passed a different hot spring, otherwise, we would have had no idea it was here!


What is the Boiling River?

The Boiling River is a section of the Gardner River where a nearby hot spring flows down the hillside and mixes with the cool waters of river, making it a comfortable temperature to swim in. The mixing of the hot and cold waters essentially creates a natural hot tub where you can sit and relax.

Where is the Boiling River Located?

The Boiling River is located in the north west corner of Yellowstone National Park, about 2miles north of Mammoth Hot Springs and about 3miles south of the North Entrance.

How to Get to Yellowstone’s Boiling River

From Mammoth Hot Springs: Drive North on Rte 89 for about 2 miles. The road will turn several times as you do gown the hillside, shortly thereafter you will see parking areas on both sides of the road.

From the North Entrance: Drive South on Rte 89 for just under 3 miles. You will crest the top of a hill and as you start to go down into a valley just before crossing the river, there will be parking areas on both side of the road.

Finding The Hot Spot In The River

After parking in either of the parking areas (cross the road if needed), go to the trail that starts from the east parking area. There’s a sign with rules about the river and also bathrooms if needed. Follow the trail along the river for about 1/2 – 3/4mi.

While walking along the trail, remember you’re still in Yellowstone, so there’s still lots of wildlife to be aware of. We saw 2 elk crossing the river ahead of us, one of which was a male with a full antler rack that let out an elk bugle while in the middle of the river. It was pretty amazing and one of the highlights of the entire trip.


The trail ends where the hot springs meet the river, thus creating the Boiling River. It will be very obvious as there are wooden makeshift guard rails to keep people out of the hot spring. Plus there will also be a bunch of other people.

In the river, people have created “hot tubs” of sorts using the rocks from the river which show the prime spots for soaking. There are a few up-river from the entry point to the river and lots more down-river. There’s about a 1-2ft wide ribbon of the river where the temperature is just right. Any closer to the spring is too hot and further out into the river is too cold. These rock-ring “hot tubs” are in the section of the river that’s “just right”, so if available, you want to try to get a tub for yourself and group of friends. These rocks also help to slow and breakup the currant of the river – the river currant can be very strong depending on the time of year, so use caution when wading out into the river.

The river is too shallow to actually swim in, so all you’ll be able to do is sit and soak in the “hot tubs”. Sitting, the river will likely be about waist-high on most people. If you’re just wading around, the river may get up to your knees, which means you can still roll up your pants lets and enjoy this phenomenon even if you don’t have a swimsuit.

When is the Boiling River Open?

The Boiling River is open during daylight hours only from 6am to 8pm and closes at dark. It’s usually closed during the Spring and early Summer because the melting snow raises the water levels, makin it dangerous to be in the river. Go during the late Summer, Fall or Winter.

What Is The Temperature of The Boiling River?

The temperature of the Boiling River varies depending on where in the river you’re standing. The waters coming out of the hot spring are approximately 135 degrees Fahrenheit, but can sometimes reach up to 140 (and as of 2015 are starting to get hotter every year). This mixes with the cold water of the river to create a much more comfortable temperature. The further away from the hot spring water you are, the colder it becomes.

The river itself is really cold and once you start getting to the area where it’s mixing with the hot spring water, it gets VERY HOT VERY FAST. A couple of inches can make a big difference in the temperature you experience. Even once you find a distance from the hot spring that’s comfortable, you’re still going to get waves of hotter water and waves of colder water as the currant of the river passes by you.

In general, green = so hot it will burn you. The areas of the river that meet with the hot spring water tend to have a green “algae” or something on the rocks. It’s likely some type of bacteria similar to what causes the colors in the other hot springs in the park that hasn’t been disturbed since it’s too hot of an area for a person to touch. Avoid the green rocks and you’ll be just fine.

What Should I Bring?

Water shoes: Rubber Sole Mesh Water Shoes
If possible, I highly recommend bringing water shoes. I wish I had them. The river isn’t mucky or slimy or anything – it’s almost all rock. But, the area where you first enter the water is in the cold part of the river and it’s COLD, causing your feet to get a little numb as you walk through the water, which can make you less sure-footed. Most everyone is quick to lend a helping hand for those who need some additional balance. You also have to walk over some larger rocks that create the rings of the hot tubs as described above, and with a strong currant going over those rocks, you can’t always see where everything is.

Swimsuit and Towel.
No skinny dipping is allowed, so if you want to get into the water any deeper than your knees, you need appropriate swimwear. Honestly, no one is there checking, so if you want to get in in your tshirt and shorts, that’s really up to you. Just don’t get naked, that would be awkward for everyone involved. Towel is for drying off for your hike back to the car. Not required, but a good idea to make the trip more comfortable.

Especially if you’re pale and pasty like me and want to keep it that way. There’s no shade at The Boiling River, so you’re gonna want some protection from the sun.

No Alcohol.
Alcohol or other libations are not allowed.

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