Bend, OR: South Sister via Obsidian Trail

Link pumice and obsidian fields with expansive alpine meadows on this challenging trek to the top of South Sister, a glacier-capped volcano in the Cascade Range.

Heading out the door? Read this article on the new Outside+ app available now on iOS devices for members! Download the app.

Twenty miles west of Bend, the rugged, glacier-covered slopes of South Sister rise dramatically above Deschutes National Forest. The tallest of a trio of volcanoes known as the Three Sisters (and Oregon’s third tallest peak), South Sister’s summit reveals dramatic views across the Cascade Range.

Follow the Obsidian Trail

Start this challenging trek at Frog Campground and head southeast on the Obsidian Trail. You’ll gain roughly 5,500 feet of elevation and travel from forested landscapes to stark slopes covered with volcanic pumice and obsidian. After 20 miles, rest by a small lake on South Sister’s false summit before the final, 1-mile push to the summit (which gains almost 2,000 feet of elevation). Savor the sky-high views from the crater rim—Middle Sister, North Sister (and Mount Hood, on very clear days) can be seen to the north—then follow the same route back to the trailhead.

-Mapped by Trung Q. Le


Trail Facts

  • Distance: 35.1



Location: 44.203079, -121.870728

Hike southeast from the Obsidian Trailhead at the east end of Frog Campground. Note: Before you hit the trail, purchase an annual Northwest Forest Pass, or buy a day pass at the trailhead.


Location: 44.19632, -121.861999

Continue straight on Obsidian Trail @ T-intersection. The trail to the right leads to Spring Lake and White Branch Creek. Ahead, the dusty path climbs gradually under the covering of trees, shaded from any sunlight.


Location: 44.185551, -121.835602

Catch views of North Sister to the east through the gaps in the trees.


Location: 44.18327, -121.829598

Bear right onto the Obsidian Trail @ Y-intersection with Glacier Way Trail. Ahead, the terrain changes dramatically from forested landscapes to stark, rocky slopes of pumice and obsidian.


Location: 44.166851, -121.818298

Bear right @ Y-intersection onto the Pacific Crest Trail (PCT). The trail on the left climbs to Obsidian Falls and Scott Spring.


Location: 44.15168, -121.8171

Check out the first of many views of The Husband (to the southwest). The forest begins to open up as the trail inches closer to Linton Meadows.


Location: 44.142551, -121.820999

Stay left on the PCT @ the Y-intersection. Depending on the time of year, wildflowers blanket the ground in vibrant colors. For overnight options, turn right @ Y-junction and follow trail roughly 1 mile to Linton Meadows, a popular camping area.


Location: 44.125351, -121.821098

Bear left on the PCT @ Y-intersection. The trail to Racetrack Meadows veers off to the right.


Location: 44.114101, -121.811203

Pass a large, seasonal pond (good place to filter water).


Location: 44.08662, -121.818398

Pass a small lake. Filter water here if your reserves are running low.


Location: 44.084122, -121.820297

Bear left on the PCT @ Y-junction. Ahead, the trail rounds to the southeast, passing potential campsites in 0.5 mile.


Location: 44.079571, -121.818001

Hike across the Mesa Creek drainage (which resembles a flooded plain). Top off water bottles in the creek.


Location: 44.065361, -121.810699

Hike south through the Wickiup Plains. Volcanic pumice blankets this flat, expansive (and barren) area rimmed by conifers. The Rock Mesa obsidian flow rises to the east next to the trail.


Location: 44.05983, -121.808899

Bear left (southeast) @ Y-intersection toward Devils Lake. The PCT veers to the right toward Sisters Mirror Lake.


Location: 44.053299, -121.802597

Take in the first views of Broken Top volcano to the east. Continue heading southeast.


Location: 44.04855, -121.790802

Turn left @ T-intersection toward Moraine Lake. The trail winds to the northeast along Kaleetan Butte.


Location: 44.055229, -121.771004

Turn left @ 4-way intersection onto the South Sister Trail. Hike north. (Devils Lake Trail on the right is the standard route to South Sister.) Overnight options: Continue straight @ 4-way for camping near Moraine Lake.


Location: 44.062019, -121.769096

Continue straight @ 3-way-intersection toward South Sister. The trail winds through an open area dubbed the “golf course.” Tufts of grass and patches of dirt cover this broad expanse.


Location: 44.090778, -121.768898

A blue lake marks South Sister’s false summit. Take a break here and enjoy the view of Broken Top to the east. Next, head north for the final push to the summit.


Location: 44.10038, -121.772697

Crest South Sister’s summit (Teardrop Pool fills its crater). Next, turn right and follow the rim to the east and north to reach the true summit.


Location: 44.103252, -121.769791

South Sister (10,358 ft.): Savor sky-high views from Oregon’s 3rd tallest mountain. Look north to find Middle Sister, North Sister, and Mount Jefferson (and Mount Hood, on very clear days). Follow the same route back to the trailhead.

North Sister

Location: 44.18528, -121.835289

©Trung Q. Le

Obsidian and Pumice

Location: 44.181957, -121.82756

The Obsidian Trail traverses obsidian and pumice rock fields.
©Trung Q. Le

North and Middle Sister

Location: 44.17297, -121.827217

©Trung Q. Le

The Husband

Location: 44.15068, -121.816917

View of The Husband at sunset from the PCT.
©Trung Q. Le

Mesa Creek Meadows

Location: 44.078461, -121.817436

©Trung Q. Le

The Wife

Location: 44.066681, -121.811172

©Trung Q. Le

Rock Mesa Obsidian Flow

Location: 44.062859, -121.809715

View of Rock Mesa and South Sister from the Wikiup Plains.
©Trung Q. Le

Wickiup Plains

Location: 44.06477, -121.810394

Looking south at the desolate open plains.
©Trung Q. Le

Broken Top

Location: 44.052803, -121.802162

©Trung Q. Le

South Sister

Location: 44.062798, -121.769241

View of South Sister from the “golf course.”
©Trung Q. Le

Broken Top

Location: 44.084503, -121.768166

View of Broken Top from South Sister.
©Trung Q. Le

False Summit

Location: 44.092392, -121.770058

View of the lake at the South Sister false summit. The true summit can be seen up ahead.
©Trung Q. Le

Summit Views

Location: 44.100067, -121.77272

Views south from the crater rim of South Sister.
©Trung Q. Le

Summit of South Sister

Location: 44.100376, -121.772675

View of Teardrop Pool. The true summit can be seen ahead.
©Trung Q. Le

Trending on Backpacker