Rattlesnake Grade

Clarkston to Enterprise

Inland Northwest · Washington · United States

Key measurements

Distance

85.3 miles

Elevation gain

7,835 ft

Elevation loss

4,904 ft

High point

4,869 ft

Low point

740 ft

Net change

2,922 ft (829 ft to 3,752 ft)

Route type

point-to-point

Route Overview

This 85.3-mile route connects the low elevation of the Snake River valley at Clarkston, Washington, with the high mountain basin of Enterprise, Oregon. The ride is defined by stark geographical contrasts: it transitions from river basin floor to high rolling agricultural plateaus, drops into the dramatic depth of the Grande Ronde River Canyon, climbs back out along the famed switchbacks of Rattlesnake Grade, and traverses timbered high country before settling into the Wallowa Valley.

Accumulating over 7,800 feet of elevation gain and nearly 4,900 feet of loss across its short distance, this is an intensely undulating run. The lowest point (740 feet) occurs almost immediately upon leaving Clarkston, while the high point (4,869 feet) sits near mile 62.3 on the timbered crest north of Enterprise.

Key Segments & Geographic Transitions

Snake River Canyon to Grande Ronde Gorge (WA-129) — Miles 0.6–46.5

Beginning near the Snake River in Clarkston, WA-129 tracks south through Asotin before climbing abruptly away from the river into the high agricultural rolling hills around Anatone. After rolling across this high prairie, the highway plunges into the Grande Ronde River drainage via a series of tight, steep descents carved into basalt walls. The segment crosses the Grande Ronde River at the canyon floor near Boggan's Oasis before commencing the northern, ascending leg of Rattlesnake Grade up toward the Oregon state border.

Rattlesnake Canyon Ascent to Wallowa Valley (OR-3) — Miles 46.5–85.3

Crossing into Oregon, the road becomes OR-3 and continues its tight winding climb out of the Rattlesnake Creek canyon structure. Once clear of the rim, the character shifts to high-altitude ridge riding through open forest and grazing lands near Flora and Paradise. The road gently rolls along the plateau, cresting the route's summit at 4,869 feet near mile 62.3, before dropping smoothly into the broad, mountain-framed agricultural expanse of the Wallowa Valley, terminating in Enterprise.

Seasonal & Environmental Context

Elevation drives the environment on this route. Temperature swings can be extreme: mid-summer afternoon heat in the sheltered floor of the Grande Ronde Canyon routinely exceeds 100°F, while the high plateau sections above 4,500 feet remain significantly cooler.

In early spring and late autumn, cold air and moisture pool in the shaded basalt cutouts of Rattlesnake Grade, creating localized ice hazards long after the sun has cleared open sections. Gravel washed from canyon cutbanks is common after rain events. Agricultural machinery is frequently encountered on the plateau stretches around Anatone and Flora during summer harvest season.

Logistics & Services

Full commercial services exist at both termini (Clarkston and Enterprise). Intermediate services are extremely sparse.

Boggan’s Oasis, situated at the Grande Ronde River crossing near mile 30, is the sole intermediate point for fuel and food along the route. Because operating hours there can vary seasonally, do not assume intermediate fuel is available; depart Clarkston with enough range to reach Enterprise comfortably. Cell coverage drops out entirely inside the Grande Ronde River Canyon and remains spotty across much of the timbered plateau on OR-3.

Important Considerations

Basalt Rockfall: The steep canyon walls along Rattlesnake Grade are prone to erosion. Sharp, loose basalt rock frequently collects on the road surface in blind corners. * Open Range & Wildlife: The timbered high country of OR-3 between the border and Enterprise features sections of open range where livestock may be on the roadway. Deer and elk are especially prevalent near the high point (mile 62.3) during dawn and dusk.