Union Falls Trail

Overview

Union Falls is the headline waterfall of Yellowstone’s Bechler “Cascade Corner” — a broad, two-pronged curtain around 250–260 feet tall in a lush, wet corner of the park. Most hikers approach it as a long day hike of roughly 16 miles round-trip (reports range 15.7–17.4 miles depending on trailhead and spurs). The terrain rolls gently with modest total gain (often cited under 1,000 feet, though trackers sometimes report more). Expect solitude, forest walking, and a jaw-dropping finale.

Route and What You’ll See

From the Cascade Creek/Grassy Lake Road approach near Grassy Lake Reservoir, you’ll quickly deal with early creek crossings and then a mandatory ford of the Falls River — a defining feature of this hike. Past easy crossings near Proposition Creek, the trail follows historic tread (including an 1880s wagon route) toward Mountain Ash Creek. The final mile steepens and gets sandy before a rim viewpoint reveals Union Falls fanning over dark rock with a second stream joining from the side. It faces west and photographs best in the afternoon. Descending to the very bottom is not advised due to steep, wet slopes.

Side trips sweeten the day: a short spur leads to Ouzel (Scout) Pool, a geothermally warmed, lukewarm swimming hole below a small falls — a popular mid-hike soak. Near the start, a brief detour can visit Terrace Falls. Along the way you may pass the small Union Falls Ranger Station cabin.

Difficulty and Conditions

The trail itself is mostly moderate, but the distance and the Falls River ford make this a strenuous day for many. The ford can be ankle to thigh deep and swifter earlier in the season. Trekking poles and water shoes help on the rocky, volcanic riverbed (obsidian and basalt underfoot can punish bare feet). Expect stretches of dusty or sandy tread, especially near the end, and occasional horse traffic — yield appropriately.

Wildlife and Setting

This wet, forested corner lives up to its “Cascade” name with creeks and waterfalls everywhere. Late summer often brings huckleberries and other berries. Bear sign is common — travel smart and carry bear spray.

Best Time to Hike

Mid- to late summer into early fall is the reliable window. The Falls River is notably safer and easier to ford from late July through August once snowmelt recedes. Warm weather also makes a dip in Ouzel Pool more pleasant. For photos, aim to reach the viewpoint in the afternoon when the west-facing falls light up. Start early to manage mileage, bugs, and any delays at crossings.

Tips and Tricks

• Plan your day around the Falls River ford; avoid early season when flows are high.
• Bring poles and dedicated water shoes/sandals for the ford; keep dry hiking shoes for the rest.
• Pack ample water and calories — many hikers treat this as a full-day outing.
• Expect a rough approach on Grassy Lake Road; the short dam access spur can be steep. Check conditions before you go and allow extra time.
• Pets aren’t allowed on park trails, and if you’re turning this into a backpack, a backcountry permit is required for overnight stays.

If you want a shorter day with more roadside drama, there are plenty of easier waterfall walks elsewhere in the park — but for a remote, rewarding objective, Union Falls is a standout.