Union Falls Trail is a 15.4 mile heavily trafficked out and back trail located near Yellowstone National Park, Wyoming that features a waterfall and is rated as difficult. The trail is primarily used for hiking, running, camping, horses, and backpacking and is best used from May until September. Horses are also able to use this trail.

Distance: 15.4 miles Elevation Gain: 1,938 feet Route Type: Out & Back

backpacking

camping

hiking

horseback riding

running

forest

river

views

waterfall

closed

no dogs

It has been reported this trail has a temporary closure due to COVID-19. Please see the park's website for up to date information. Union Falls is the second highest waterfall in Yellowstone, towering above at 260 feet. The falls is very unique in shape and serves those bringing cameras very well. Union Falls is located in the southwest section of Yellowstone. Formed as two creeks come together and fall over 250 feet. Union Falls is very impressive and worth the hike to get to.

hiking
bugs
flooded
muddy
snow
1 day ago

This is a gorgeous hike! I went on June 29th and it still had quite a bit of melting snow in the swampy parts. Make sure you pack water shoes because you do have to cross about 50 yards of knee to waist deep water. There were only two major crossings, but you should have water-proof hiking shoes because there is a lot of water and mud on this trail. The bugs got pretty bad when we took the detour off to the "hot springs." It was a nice swimming hole, but not very warm. The waterfall was absolutely breathtaking and rewarding at the end of the trail! It's a must see! It is a bear frequented area, so bring best spray and make lots of noise. We brought a. 45 handgun, but remember you are not allowed to shoot animals here, even in self-defense. I still think our lives are more valuable than a bears though so better safe than sorry. Noise to ward them away first, bear spray of they're aggressive second, and as an absolute last resort we had a handgun ready. But, it was never necessary. Being lots of water and pack a lunch for this beautiful all day hike. (we tracked our hike and had it around 21 miles there and back, so the length is off from the description)

2 months ago

I hiked this trail in August 2018 with two friends and to date its still my most memorable experience hiking! I absolutely Love this trail! It's definitely not easy to cross the river when it's completely swollen and flowing so quickly as it was for us. Pictures we saw of the trail showed the river at ankle deep on kids but when we cross it was nearly chest deep. Make sure you bring trekking poles for stability when crossing as there could be alot of runoff from the surrounding areas. Some sections are pretty tight with alot of brush and others wide open on slick rock. This trail is shockingly beautiful and you won't regret a moment of it especially when you make it to the falls!!

hiking
8 months ago

Honestly, the trail itself is quite lackluster, just pines and the occasional creek. There is a creek you have to cross about a mile and a half in that, at least the day I did it, will reach up to your knees at a point, but is mostly ankle to calf deep. Despite the actual hike however, the waterfall at the end is worth it. One of the most beautiful I've ever seen in my life, incredibly unique, and rather solitary so no worries of overcrowding, I was the only one there. So if you're looking for a challenging or interesting hike, this isn't the one for you, but I would recommend it for the waterfall alone.

hiking
8 months ago

Amazing! The trail had some flats and ups and downs both ways, but on the way back there was about a mile uphill, but not too strenuous. The waterfall was beautiful, and the slightly warm springs were fun. It was a cooler day and there were hardly any bugs this time!

hiking
9 months ago

I would highly recommend this trail!! Beauty in all directions! Amazing things to find! So worth the time and miles! Pictures do not do the waterfall justice and the hot springs are so worth it!!!

hiking
bugs
9 months ago

hiking
9 months ago

trail was wonderful took my 4 boys and girlfriend on it horse flies were bad and mosquitos but the falls was well worth it was blissful didnt go to scout pool . camped overnight gotta love yellowstone weather luckily got tents up before rain and hail.

hiking
9 months ago

Very beautiful trail. 16 miles round trip. There is a 20-30 foot river a mile from parking. The river is fairly easy to pass. Didn’t see any bears:( the way back out is a little harder than into Waterfall. At the bottom is a very nice breeze! The hike fairly moderate but long. The only access to water is from rivers.

hiking
bridge out
bugs
9 months ago

This is a truly magical trail! You begin by hiking into Yellowstone National Park and have many adventures ahead of you from there. You have to wade across some moving water about a half a mile from the beginning (and thus also the end) of the hike. The waterfall is really sweet and it is possible to traverse down to it off trail, though it’s pretty steep and very slippery. Go the extra mile or so at the little fork to go to the warm (not hot) spring and chill. There are many horse flies and mosquitoes throughout so bring your bug spray! It’s not too heavily trafficked but it seems like a popular Boy Scout route.

hiking
9 months ago

mosquitos were not fun. next time I'm doing it in late August or sep

hiking
bugs
10 months ago

This was a difficult hike especially on the way out. This was only my second hike and I’m outta shape; just to put it in perspective. It’s about 9 miles to view the gigantic beautiful waterfall! Some of the group I hiked with went off trail, steep, slippery terrain down to the waterfall. On the way back we turned off onto the trail that led to the hot spring. This was the best part by far!! Temp was perfect for the hot day that it was! Able to jump off rocks. Mosquitos were thick all day and horse flies swarmed the hot spring. Still worth it though. Nine mile hike out felt like it was 99% up hill.

hiking
11 months ago

Nice hike with an incredible falls at the end. the trailhead has a pretty long and sometimes bumpy road but it is worth it. Only have to ford one river without a log and it wasn't bad. Very nice area.

hiking
Wed May 15 2019

Great hike I’m a camp loller right next to this hike and have done it many times, the view is most bodacious. Just watch out for cardiac hill.

Tue May 14 2019

Wicked hike!

Wed Mar 13 2019

love that trail! many boyscouts use this trail some days alot of people hiking. guess that goes with beautiful places many wild flowers and a perfect place to ride horses!

hiking
Wed Mar 06 2019

Loved this hike!!! We did this hike in late August (absolutely no bugs). It’s long but worth every single step. Plan for water crossings. Also, I think the trail is longer than 15 miles. Our GPS had us well over 19 miles. We highly recommend this hike.

Sun Oct 14 2018

One of my all time favorite hikes! Make sure to plan accordingly for river crossings, you’ll want to be able to take of long layers/have shorts for wading. Water shoes are a must! Scout hole provides a perfect resting place before venturing back out.

Thu Aug 30 2018

I’ve done the hike 7 times and it’s been worth it every time. Swimming in ouza pools is a party too!

hiking
Tue Jul 24 2018

Fording Rivers Unique

Fri Jul 20 2018

This trail is more moderate than difficult. However, the distance is tiring. I would say it is harder to hike back out than it is to hike into the falls. It took my fiancé and I about 3 hours to get to the falls and 4 hours to get out. This trail is absolutely stunning. It is well worth the distance. Getting to the trail is kind of tricky. It will feel like you’ve been driving forever, but just keep going. As soon as you get to Grassy Lake Reservoir Dam, the road to the trail head is at the bottom by the spillway. The trailhead is not posted at the beginning. It’s on the right hand side after you crossover the spillway(walking). If you do not have four wheel drive I would recommend parking at the dam and walking down the road. It’s not that far. Don’t forget some water shoes or sandals! You will be crossing a river. Also bring LOTS of water. YOU WILL NEED BUG SPRAY. We used an entire can of spray on this hike. The bugs are thick. We ate lunch at the falls and it was definitely a memorable time. ✌️

hiking
Wed Jul 11 2018

Hello my fellow camp Lollers ;) me as well decided to 5 star my most favorite bodacious hike :) can't wait to do it again this summer

backpacking
Tue Jun 05 2018

Quite possibly one of the best destinations in the park. Takes a bit of effort to get to the trailhead, but definitely worth it. I think it's best done as an over night hike so you have more time to enjoy the falls and relaxing in the nearby Ouzel/Scout Pool. The river crossings are typically much too high in the spring, usually the hike isn't really accessable until mid July at the earliest. And just as everyone else has said, you need bug spray!

camping
Thu Feb 22 2018

Well worth the hike will do again

backpacking
Tue Oct 03 2017

great trail.... away from all of the people in YNP... bring deet if hiking in summer.. tons of mosquitoes and flies.. a little difficult when hitchhiking to the trailhead... I hitched from old faithful to the start of the dirt road... then off and on until I got to the trailhead... I think I spent more time hitchhiking to the trailhead than on the trail! haha .. fun trail.. wide river ford at the beginning..

hiking
Tue Sep 26 2017

I have always come in from Fish Lake. This trail features three river crossings, which for me adds to the fun, and skips the elevation gain of the Grassy Lake trail. About the same total distance. Hardly ever meet anyone on this trail.

hiking
Mon Sep 04 2017

Great hike, came back in the dark, couple creek crossings, one big one . The water at Ouzel Pool was amazing. Heading back before the season ends. Falls was beautiful, the pool was the best.

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