Umatilla Rock via Monument Coulee
Central WashingtonBest Mar–May, Sep–Nov
A basalt labyrinth loop through Ice Age flood geology below Dry Falls.
About This Trail
The trail loops around the base of Umatilla Rock, a narrow basalt formation standing in the coulee below Dry Falls. This landscape was carved by the Missoula Floods roughly 15,000 years ago, when 800-foot walls of water roared through at highway speeds. The rock pillars, labyrinth formations, and sheer coulee walls left behind make this feel more like southern Utah than central Washington.
The loop follows a red-marked path counterclockwise around the rock, passing through a basalt labyrinth on the south side before connecting to an unpaved road that returns to the trailhead. The terrain stays mostly flat with minor elevation changes. Spring brings wildflowers to the coulee floor and water levels in surrounding lakes run higher. Summer gets hot with no shade, but fall and early spring are ideal.
The Dry Falls Visitor Center sits 400 feet above on the coulee rim and is worth the stop for context on the flood geology. Deep Lake Road access can be gated closed seasonally, so check before driving in. Poison oak grows along some trail sections.
Astronomy
Trail Conditions
Scorecard
Safety & Considerations
Today's Hazard
- Strong sun — sunscreen, hat, and sunglasses recommended
Persistent Hazards
- poison oak along trail sections
- no shade or water
- Deep Lake Road seasonally gated
- extreme summer heat
Getting There
From SR-17 at MP 92.5, enter Sun Lakes State Park and follow signs toward Deep Lake. Turn left onto unpaved road toward Perch/Dry Falls Lakes. Park at the kiosk after 0.4 miles. Discover Pass required. Deep Lake Road NE may be gated closed depending on weather and season. Check conditions before driving in.
From the parking kiosk, follow the red-marked trail counterclockwise around Umatilla Rock. The labyrinth formations on the south side are the scenic highlight. The return leg follows an unpaved road back to the trailhead. Consider stopping at the Dry Falls Visitor Center on the rim above for geological context.
Any time of day works in spring and fall. In summer, start early to avoid peak heat. The visitor center has set hours, so plan accordingly if combining the hike with a visit.
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