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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.

Length15.4 miElevation gain1,938 ftRoute typeOut & back
BackpackingCampingHikingHorseback ridingRunningForestRiverViewsWaterfallFeeNo dogs
Description
Waypoints (0)
Contact
Getting There

Yellowstone closes trails annually to reduce encounters between bears and humans during certain times of the year. See here for bear closure info: https://www.nps.gov/yell/learn/management/bearclosures.htm Additionally, roads in Yellowstone are closed annually during winter. Before you head out, see Park road closures here: https://www.nps.gov/yell/planyourvisit/parkroads.htm Yellowstone National Park charges a fee to enter. Fees are $35 per vehicle or $30 per motorcycle. If you are entering on foot, horse, or bike the fee is $20 per person. You can also purchase a park specific annual pass for $70. 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.

Yellowstone National Park PO Box 168 Yellowstone National Park, WY 82190-0168 307-344-7381 (recorded information and an option to speak with someone) Additional info: http://www.nps.gov/yell/contacts.htm Wyoming Business Council Tourism Office, Frank Norris Jr. Travel Center, I-25 & College Drive , Cheyenne, WY, 82002-0660, Phone: 307-777-7777, Fax: 307-777-6472

Directions from US 287: About 2 miles south of the park, just before Flagg Ranch, take a right on the Ashton-Flagg Road. Turn right (west) about 1/4 mile, the left side of this fork goes to the campground. The pavement continues about 2 more miles before gradually giving way to a badly gravel road. The trailhead is just after the spillway at the end of Grassy Lake Reservoir. Two wheel drive vehicle are advised to park at the top of the dam. Getting back up the hill can be tough without 4-wheel drive.

Weather
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Reviews (115)
Photos (90)
Activities (72)
Completed (255)
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Evan Toren
Yellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarSeptember 20, 2020
Walking

Trail was well marked and clearly gets used almost every day. Hopped over a few downed trees and a couple places were muddy but not too much trouble. Water is available along the way. Nice trail! Really long for one day. Budget for at least 7 hours of walking in good weather, maybe more like 9. No bugs in Mid-September. People were very friendly.

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Santiago Zuluaga
Yellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarSeptember 15, 2020
Hiking
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Rafe Preston
Yellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarGray StarGray StarSeptember 13, 2020
HikingGreat!

The hike itself is a little boring if you are coming from some pretty amazing views in the Tetons, but the final destination is pretty amazing. The creek crossing at around a mile in is pretty cold but in the second week of September only about knee high. The return across wasn't as bad as the Temps of my body and the air had gone up. The falls are truly amazing and we were the only ones there for 30 minutes. Small trail even leads down the hill to the bottom of the falls. The mist alone down there gets you pretty soaked! Overall pretty nice hike. Took my wife and I almost 7 hours. A little slowed by the crossing as I brought Keen water shoes just for the crossings so I didn't get my hiking shoes wet.

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William Bowen
Yellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarSeptember 13, 2020
Hiking
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Evan Toren
Yellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarSeptember 12, 2020
Hiking
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Evan Toren
Yellow StarYellow StarYellow StarYellow StarYellow StarYellow StarGray StarGray StarGray StarGray StarSeptember 12, 2020
Hiking
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R G
Yellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarSeptember 6, 2020
Hiking

We did this hike on Sept. 5. Started out about 7:30 am from the Fish Lake trailhead. The road in a horrible but passable with a higher clearance vehicle. The Fish Lake trailhead is almost flat the entire way until it meets with the junction of the Grassy Lake trail. There is a little climbing to do after that. The three river crossings were up to our knees with Ash Creek being a bit deeper towards the middle. The meadows were pretty dusty and well traveled by horses. It wasn’t crowded at the falls and it was as beautiful as ever. We enjoyed our lunches there. Scout Pool was a bit more crowded but still enjoyable. There were no bugs to bother us anywhere. There were lots of butterflies and dragonflies around the pool area. Got back to the parking area at 5:30.

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Nathan Zurcher
Yellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarAugust 31, 2020
HikingGreat!

We did this trail as a long day hike. Drove to the trail from Ashton and got to the trailhead about 915AM. We arrived to the waterfall by 1230, went to the pools on the way back, and finished the hike around 530. The river crossing was knee high and fairly easy in water shoes that we brought along. The bugs were bad around the water parts of the hike (especially near the end of the hike at the last river crossing) however we didn't need bug nets like someone else had suggested. Bug spray did the trick. The hike was more scenic than expected and the waterfall is absolutely stunning. The pools are well worth the short stint off the trail (1/2 mile maybe) and swimming in them was actually the highlight of the trip! One of the best hikes I've done in a long time.

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Anna Gee
Yellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarAugust 28, 2020
Hiking

The falls were gorgeous! If you have time I also recommend visiting the hot pool, it’s only like a mile away from the falls. You should note that there is a bathroom behind the ranger station (pictured) it’s an open bathroom, so there’s no privacy; it’s just you, the forest, and the open toilet

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Cara Garr
Yellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarAugust 26, 2020
BackpackingGreat!

Great hike. Beautiful falls. Bugs have calmed down a bit but at night make sure you deet up. We camped and then headed to falls on a Saturday. Definitely busy on a Saturday.

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Cole Messina
Yellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarAugust 24, 2020
Backpacking
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Cole Messina
Yellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarAugust 24, 2020
Backpacking
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Cole Messina
Yellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarAugust 23, 2020
Backpacking
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Lance Christensen
Yellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarAugust 23, 2020
Hiking

Awesome hike

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Danny Kalb
Yellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarGray StarGray StarAugust 17, 2020
Hiking
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Rory Counts
Yellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarAugust 15, 2020
HikingBugsGreat!

Some backcountry magic right here. Spent the nights at 9u2 and 9u4 and hiked to union falls and the hot springs. Incredible ending to a moderately difficult hike with a few river crossings. A bit more straining on the way out with a good bit of it uphill.

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Thomas Lynch
Yellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarAugust 3, 2020
HikingBugsMuddy

The waterfall is worth the hike! Union falls is incredible and the small swimming pool nearby it is a great way to refresh before the hike out. We went down the last little gnarly road and parked below the dam at the trailhead, which is located at the far point of the lot (not marked) over by the giant cement Spillway. You’ll actually walk for 5 minutes and then be greated by a “now entering Yellowstone” trailhead sign. After 1.3 miles you’ll hit the river cruising which was knee deep on a 5’11” individual late July. I recommend wearing wool socks then taking them off and going in your shoes without socks for the crossing before putting them back on afterwards. Worked great for us. Face slightly upriver with a bend in your knees and a slight body bend forward and the resistance of the fast moving water should be neutralized enough to feel safe. The SW corner of Yellowstone is the wettest region so prepare for a TON of mosquitoes during several sections, especially towards the end. Buy a ‘sea to summit’ brand head covering bug net to put over a hat will make a night and day difference for your enjoyment on the hike. The waterfall needs no review, is the greatest hidden waterfall the woods have ever offered. When you get to the final split where there are a bunch of horse tie ups, go right to the waterfall and enjoy, then take the other split 0.3mi to a small waterfall which is a great swimming hole! We stayed at campsite 9U4 which was spacious but so buggy it was straight into the tent with no fire for us that night. Enjoy union falls, it’s worth it

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Heather Milestone
Yellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarAugust 2, 2020
HikingBugsMuddy

Did this hike 7/28 and had not read reviews before doing this hike that there was a river crossing a little over a mile in. We were up to our knees in water, and it would have been nice to have a pair of sandals or water shoes. The trail itself is pretty uneventful, but the waterfall definitely makes it worth it. It was gorgeous, and only saw 3 other groups on the trail. Be prepared for a lot of unshaded uphill on the way back and bugs along the way. It was still all worth it. Also, only drive your car the last portion to the trail head if you have 4 wheel drive. Park your car above if you don’t!

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Nathan Geddes
Yellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarJuly 27, 2020
HikingBugs

Excellent as always! But for some reason the bugs are terrible this year. Take lots of spray especially if you plan to get wet in the waterfall or the swimming hole.

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Caleb Widrick
Yellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarGray StarGray StarJuly 25, 2020
Hiking

Not the most exciting hike but the payoff is huge.

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Chelsey Chapman
Yellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarJuly 20, 2020
HikingBugsMuddy

Absolutly beautiful hike. We wanted to take our time in the area so we backpacked in. Glad we did! The bugs, like everyone else says, are relentless. We at one point set up our tent solely to get some peace from the bugs. Went through two cans of bugs spray and still got eaten alive. That being said we did take the small hike to the base of union, and got soaked, then went to Scout falls close by and jumped into the water, so completely wet. So there was lots of reapplying of the bug spray. I would not rate this hike as hard though, I would say moderate at best. And worth every second!

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Chris Wilfong
Yellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarJuly 18, 2020
HikingBugsMuddyRocky

Our group completed this hike today and we finished it the same day. It can be done in one day but it can be brutal at time but worth it at the end. We also went to the swimming area, total miles covered was a little over 17 and our total hike time was 6.5 hours

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Andrew Schlichting
Yellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarJuly 18, 2020
HikingGreat!

Best hike in Yellowstone! Literally saw 10 people the entire day. It was nice to get away from the crowds. My GPS put the hike at 16.7 miles from the parking lot. I was pleasantly surprised with the condition of Grassy Lake Road. It was in great condition until about 2 miles from turnoff to the parking area (I think it was recently graded). Even the last 2 miles could very easily be managed in a normal, 2WD car without high clearance. However, I would absolutely not attempt to go down into the parking area without a 4WD vehicle--you will not make it up the hill to get out. It's only .2 miles so just park up above and walk down if you don't have 4WD. The trail itself was very well marked. The river is low right now--shin height for me to cross (I'm 6' tall), one brief part where it was just below my knees. There were two boggy areas about 3ish miles into the hike that are a bit difficult if you're trying to keep your 2nd pair of shoes dry. You can go around them though or stay to the side of the trail. The creek crossings after the river have logs to cross on. The bugs are relentless the entire trail. That was the only negative about the hike. Mosquitos and horse flies just non-stop swarming. Bug spray didn't help much. We didn't see any bears or really any evidence of them, but there's no doubt that's their environment so just be safe and have bear spray and store your food. The whole hike is in the forest. Overall, it was well worth putting up with the bugs for the waterfall--absolutely spectacular!

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Madalyn Young
Yellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarYellow StarJuly 14, 2020
Hiking

We went over two days! It was beautiful and well worth it. There were a crap ton of mesquitos at our campsite and the last mile and half to the falls. So bring bug spray!!

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