Union Falls Trail Description (Trailhead 9K5) - Heavy Traffic
At a height of 260 feet, Union Falls is the second highest waterfall in Yellowstone. Its unique shape makes it one of the park's most picturesque landscapes. Combine this hike with a trip to Terraced Falls Trail and you'll enjoy a rewarding day in Yellowstone's Cascade Corner.
Beginning at the Cascade Creek parking lot the trail descends steeply on a wide, rocky path to the junction with the Terraced Falls Trail at 0.4 miles (highly recommended). From this trail junction continue heading right (northeast) for a short distance where you'll ford a shallow section of Cascade Creek. Like many small streams in the park this one seems fairly benign in August but a substantial log jam just past the ford is an important reminder of just how powerful these small streams really are during the spring runoff.
For the next 0.7 miles the trail is mostly wooded and descends at an easy grade toward the Falls River. At 1.1 miles the South Boundary Trail enters from the right just before you reach the river. This is a wide and easy river to cross but in the spring the current can be deceptively fast through here. Crossing downstream of the small island located near the opposite bank makes this ford easier. Cascade Creek and the Falls River are the only two fords you'll need to contend with during this hike.
After crossing the Falls River you'll pass the junction for campsite 9F2 (★★★) and the Pitchstone Plateau Trail. Site 9F2 is a secluded campsite with easy access to the Falls River. A fly rod will help pass the time while you're camped here.
From the Pitchstone Plateau Trail junction the Mountain Ash Creek Trail climbs at a steep grade for the next 0.7 miles through lodgepole forests, gaining about 280 feet in elevation before reaching the highest point along the trail at 7,280 feet. From here you'll descend about 1.0 mile before climbing another short hill. The trail continues in a northeasterly direction before descending once again to the only vantage point at 4.0 miles. A shallow band of exposed rock has kept trees from taking root in this area and it allows for a modest view to the west across a sea of unbroken conifer trees. From this rocky overlook the trail descends steeply to Proposition Creek. A large tree that lies just upstream is the best place to ford this small stream. The trail climbs another small hill as is turns to the southwest just before descending to meet the Union Falls Trail at 5.6 miles.
From the Union Falls Trail junction turn right (northeast) and follow the well worn trail along Mountain Ash Creek toward campsites 9U4 and 9U5. At 6.3 miles you'll reach the first campsite in this area, 9U4 (★★★), is a nice site located very near Mountain Ash Creek. Just past site 9U4 the trail crosses this wide stream on a narrow footbridge made from a single pine tree.
At mile 6.5 the trail reaches the Union Falls Ranger Station where a simple A-framed structure sits beside a 30 foot tall radio antenna. Based on its narrow width and the steeply pitched roofline it's hard to imagine anyone staying in this cabin and that may explain the picnic table and the two small tents pitched nearby. According to the rangers we talked to, as many as fifty people may visit Union Falls on a typical day during the summer. On our short visit to Union Falls we had very easily encountered that many people.
From the ranger station it's a short walk to campsite 9U5 (★★★★). This area is designated a minimal impact campsite and wood fires are prohibited. The cooking area and tents sites are located near a tributary of Mountain Ash Creek which borders the campsite to the west.
As you hike the last 1.4 miles to Union Falls you'll notice the trail becomes much wider and quite a bit sandier. The trail sees a great deal of foot and horse traffic through here which contributes to these soft conditions. For the next 0.9 miles the trail climbs again but at a manageable grade. At mile 7.4 you'll reach an area set aside for stock animals, which are not permitted the last 0.5 miles to the waterfall. A food storage pole is available at this location and can be utilized by stock users and hikers. An unmarked spur trail heads north for 0.3 of a mile to a popular swimming hole known as Ouzel/Scout Pool. Hikers can swim in the thermally heated waters along this stream which is situated at the base of a small waterfall (highly recommended).
Over the last half mile the trail ascends 150 feet to an overlook adjacent to this spectacular 260 foot waterfall—the second highest in Yellowstone. Union Falls was named for the two streams that merge near the top of the waterfall. The view is absolutely breathtaking and on occasion a cool mist drifts through the trees surrounding the overlook. For a completely different perspective you can descend to the creek via the steep trail near the overlook. The view from the bottom is equally inspiring and it's a moment you won't forget anytime soon.
NOTE: Many of the trailheads along the Ashton-Flagg Road begin in the Targhee National Forest just outside of Yellowstone's southern borders. Trailheads are often unmarked and may be difficult to locate so a good map is imperative. The Ashton-Flagg Road (Grassy Lake Road) runs east and west for about 50 miles between the South Entrance of Yellowstone and Ashton, Idaho. Approximately 32.0 miles of the road is unpaved and can be difficult to travel during the spring. The road is closed during the winter. There are no services along this route. Click to view this route.
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WARNING: YOU MUST BE WELL PREPARED and carry the necessary equipment to make your hike a safe one. You are responsible for your own well-being while trekking in these remote wilderness locations. Help or rescue can be hours or even days away.
Read more about obtaining Yellowstone Backcountry Permits.
Nearby Hiking Trails
South Boundary Trail West (Trailhead 8K5)
South Boundary Trail (Trailhead 8K7)
Beula Lake (Trailhead 8K6) - A peaceful lake located at the southern end of the massive Pitchstone Plateau.
Fish Lake (Trailhead 9K3)
Grassy Lake (Trailhead 9K6)
Cascade Creek (Trailhead 9K5) - Provides access to the Terraced Falls Trail and the Pitchstone Plateau Trail.
Headwaters Campground - Headwaters Campground is located at Flagg Ranch Resort approximately 12.7 miles east of the Cascade Creek Trail. The campground has 24 hour showers, laundry facilities tent sites, and pull through RV sites with full hook-ups. Each site has a fire pit and picnic table. Click here to make online reservations or call: 1-800-443-2311. A general store, restaurant, gift shop, visitor center and gas station (seasonal) are located nearby. Get directions from the Cascade Creek Trailhead to the Headwaters Campground/Flagg Ranch.
Grant Village Campground - Grant Village Campground is located approximately 36.8 miles northeast of the Cascade Creek Trailhead and has 430 sites and full amenities. Sites are $29.00 + per night. Includes 2 showers per day. Reservations accepted. Generators are permitted from 8am - 8pm. Click here to make online reservations or call: 1-866-439-7375. A general store, restaurant, gift shop, visitor center and gas station (seasonal) are located nearby - Get directions from the Cascade Creek Trailhead to the Grant Village Campground.
Lewis Lake Campground - Lewis Lake Campground is located approximately 26.0 miles northeast of the Cascade Creek Trailhead and has 85 sites. Campsites are $15.00 per night. Reservations are not accepted. Generators are not permitted. Not recommended for motorhomes or trailers over 25' - Get directions from the Cascade Creek Trailhead to the Lewis Lake Campground.