Onion Creek to Castle Valley — Fisher Towers Back Road
Eighteen creek crossings into canyon madness.
Onion Creek Road off Utah Route 128 east of Moab looks innocent from the highway — a gravel track threading into a narrows between brick-red canyon walls. Then the creek crossings start. You’ll ford Onion Creek roughly eighteen times in three miles, the water laced with selenium that stains the rocks an otherworldly orange and white. The canyon walls tighten and the colours get stranger — purple mudstone, cream sandstone, rust iron staining bleeding down every face. Pop out on top and the Fisher Towers rise to the east: 900-foot spires of Cutler Formation sandstone that look like they were sculpted by someone who’d never seen a mountain. Drop to the Colorado River via the Thompson Canyon connector and you’re back on pavement at Castle Valley.
Moderate difficulty — this isn’t a locker trail, but the creek crossings demand at least a stock 4WD with solid ground clearance to avoid washing silt into your brakes and driveline. Check flow levels before you commit; flash flood risk is real in this canyon. Spring and fall are the call — summer heat in the canyon is punishing and creek levels can spike fast. No permit required. Camp at Onion Creek dispersed sites off 128. Moab is 23 miles west for fuel and supplies.
Trail Specs
| Difficulty | Moderate |
|---|---|
| Trail Type | Backcountry, High Clearance |
| Surface | Dirt, Mixed, Rock |
| Features | Camping, Remote, Scenic, Water Crossings |
| Length (miles) | 16 mi / 25.7 km |
| Duration | Half day to 1 day |
| Max elevation (ft) | 5600 ft |
| Best season | March-May, September-November |
| Minimum vehicle | Stock 4WD high-clearance |
| Nearest town | Moab, UT |
| Land manager | Bureau of Land Management — Moab Field Office |
| Permit required | No |
| Cell service | None |
| Water crossings | Yes |
| Dispersed camping | Yes |
| Official sources | blm.gov |
| Start coordinates | |
| End coordinates | |
| Copy both for Google Maps directionsClick to copy the directions URL · or open it directly in a new tab | |
| Find on Google | Search on Google → |
Location
Trail Conditions
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Frequently asked questions
Can a stock 4Runner or Wrangler run this trail without modifications?
Yes, a stock 4WD high-clearance vehicle handles it fine. The creek crossings are the main concern — water depth varies by season, but a factory rig with decent clearance and 4WD locked in gets through. Aired-down tires help on the loose rock sections.
Is Onion Creek passable in summer or after heavy rain?
Summer flash floods can blow out the creek crossings fast and without warning — this canyon funnels water hard. Best windows are March–May and September–November. Avoid if thunderstorms are in the forecast anywhere upstream; you won't always see the storm that kills you here.
Do I need a permit to drive or camp on this trail?
No permit required to drive the trail. Dispersed camping is allowed under standard BLM rules — 14-day stay limit, 200 feet from water, pack out everything. No fees as of current BLM Moab Field Office policy, but check blm.gov/office/moab-field-office before you go.
What's the hardest part of the trail and what should I actually expect?
The 18 creek crossings through Onion Creek are the crux — not individually brutal, but the cumulative crossings on slick mudstone bottom can catch you off guard, especially mid-trail where the canyon narrows and water has nowhere to go. The exit climb toward Castle Valley is rocky and off-camber but short.
How far is the nearest gas from the trailhead and is there any cell service on route?
Moab is roughly 20–25 miles from the Onion Creek trailhead — fuel up before you leave town, there's nothing out here. Cell service is zero for the entire 16-mile run; download your maps offline and let someone know your plan before you drop in.
Trail track
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