Union Falls
Wyoming · height not recorded · Yellowstone National Park · Last verified 2026-05-15
Union Falls is at 1,480 cfs of flow today, on the upper end of typical conditions.
Expect dry conditions today — don't drive out for this one. Flow is at 1,410 cfs (bottom 0% of the last 30 days, vs. 2,338.3 cfs average). The 7-day NOAA forecast shows no significant rain.
Right now
Streamflow
1,480 cfs
SNAKE RIVER AB JACKSON · 47m ago
Overnight
37°F
Mostly Clear
Saturday
63°F
Sunny
Today's daylight
Sunrise 5:39 AM · Sunset 9:07 PM · 15h 28m
Wildlife activity
Other park alerts
- Traffic Delays - Gardner River High Bridge(Information)
- Vehicle Entrance Reservation Not Needed(Information)
Snapshot built 3m 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 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: 1,880 cfs · 75% of last year — similar
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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