Union Falls
Wyoming · height not recorded · Yellowstone National Park · Last verified 2026-05-15
Flow at Union Falls is 404 cfs today, around its seasonal average.
Right now
Streamflow
404 cfs
SNAKE RIVER AB JACKSON · 21m ago
Overnight
53°F
Patchy Smoke
Tuesday
85°F
Patchy Smoke
Today's daylight
Sunrise 6:06 AM · Sunset 8:53 PM · 14h 47m
Other park alerts
- Traffic Delays - Yellowstone River Bridge(Information)
- Osprey Falls Trail Temporary Closure(Information)
- Madison, Firehole, and Gibbon Rivers Closed to Fishing(Information)
Snapshot built 4m ago. Sources: USGS · NWS RIW.
Union Falls is a waterfall in Teton County, Wyoming. Height has not been officially recorded. Access details and conditions have not yet been verified in person by Fallspots — the data on this page comes from OpenStreetMap and USGS GNIS.
Union Falls sits in Teton County, Wyoming. It drops along Mountain Ash Creek. The falls are inside Yellowstone National Park, a US National Park. The base sits at roughly 6,881 feet of elevation. Drive time is about 33 minutes from Warm River. A trail — Union Falls — runs within 100 meters of the marked location. No public parking is recorded within 2 km, so a longer approach is likely. This is one of the more frequently visited falls in the state by our popularity model. Source records come from OpenStreetMap and USGS GNIS.
Union Falls is a fan-type waterfall on Mountain Ash Creek, a tributary of the Fall River in the Cascade Corner (southwest) of Yellowstone National Park, in Wyoming, United States. With a height of 250 feet (76 m), it is the second tallest major waterfall in Yellowstone, exceeded only by the lower Yellowstone Falls. The falls was named by members of the Arnold Hague Geological Surveys sometime between 1884 and 1886. Geologist J.P. Iddings claims the name derives from the fact that a tributary of Mountain Ash Creek joins at the very brink of the falls, thus Union Falls. Access to the falls is via the Mountain Ash Creek trail and the Grassy Lake Road.
Is the water flowing right now?
Most waterfall sites don't tell you this. The waterfall itself is almost never gauged, but a USGS streamgage in the same watershed can tell you whether snowmelt has started, peaked, or run dry.
USGS gage 13010065 · 12 mi away
SNAKE RIVER AB JACKSON LAKE AT FLAGG RANCH WY
— Distant gauge — proxy reading, not on the same drainage.
View live discharge data →
30-day streamflow
Below 30-day average↻ Same date last year: 237 cfs · 173% of last year — significantly wetter
Compare to nearby falls
If this one isn't the right fit, here's how it stacks up against the closest documented falls. Every column is filterable on the site — not buried in 13,000 reviews.
| Waterfall | Distance | Height | Trail | Dogs | Fee |
|---|---|---|---|---|---|
| Union Falls (this page) | — | — | — | N | — |
| Terraced Falls | 3 mi | 131 ft | — | N | — |
| Cascade Acres | 3 mi | — | — | N | — |
| Rainbow Falls | 4 mi | — | — | N | — |
| Cascade Creek Falls | 4 mi | — | — | — | — |
| Iris Falls | 5 mi | 46 ft | — | N | — |
Questions visitors ask about Union Falls
Answers built from our structured data. If a question isn't here, the fact is unverified — we'd rather omit than guess.
Is Union Falls in a national or state park?
Yes — Union Falls is inside Yellowstone National Park. See the park page for fees, hours, and current conditions.
Can I bring my dog to Union Falls?
No — dogs are not allowed on trails here. Most National Park trails prohibit pets to protect wildlife. Service animals are an exception per ADA.
How far is Union Falls from a major city?
Union Falls is 23 miles from Warm River (about 33 minutes' drive).
More waterfalls in Wyoming
Where it is
44.1924, -110.8707
Sources and live status
Where we got the data, and where to check current conditions before you drive.
Wikipedia
https://en.wikipedia.org/wiki/Union_Falls
Wikidata (Q38037)
https://www.wikidata.org/wiki/Q38037
GeoNames (5841702)
https://www.geonames.org/5841702/
Last verified by Fallspots: 2026-05-15
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