Big Obsidian Flow sits inside the caldera of Newberry Volcano, in the Deschutes National Forest, about 29 miles south of Bend, Oregon. It is part of Newberry National Volcanic Monument.

This is Oregon's youngest lava flow. Rhyolite lava erupted here about 1,300 years ago, around 700 AD. The lava cooled too quickly for crystals to form, freezing instead into natural volcanic glass known as obsidian.

The flow covers about one square mile and reaches up to 150 feet thick in places. It sits at an elevation of about 6,400 feet, surrounded by a forest of lodgepole pine.

Here's the best part: you can walk across the top of this ancient lava flow. There is no fence or roped-off viewing area separating you from the landscape.

Big Obsidian Flow Geology & History

Two rock types dominate the surface.

Glossy black obsidian is heavy, dense, and has razor-sharp edges when broken.

Pale pumice is light, crumbly, and filled with tiny frozen gas bubbles.

Both formed during the same eruption, but they look completely different because of how much gas escaped before the lava hardened.

Newberry Volcano itself is enormous, covering roughly 1,200 square miles.

The caldera that contains Big Obsidian Flow spans about 17 square miles, with Paulina Peak rising to 7,985 feet above the surrounding landscape.

Geologists continue to study the flow to understand better how rhyolite eruptions behave.

Long before modern research, Native peoples collected and shaped Newberry obsidian into tools, blades, and projectile points.

The valuable volcanic glass was also traded widely throughout the Northwest.

Big Obsidian Flow Hike

A short paved path leads from the parking lot to a lower viewpoint. Even this easy walk provides a great view across the lava field and works well for people with different mobility levels.

Want to explore more? Climb the staircase and follow the 1-mile loop trail across the obsidian flow. The trail gains about 200 feet in elevation, making it generally easy, but the surface is uneven and covered with loose volcanic rock, pumice, and gravel.

Seven interpretive panels along the trail explain the eruption, local plants and wildlife, and the human history of the area. Benches provide places to rest and take in the unusual landscape.

There is almost no shade on the trail. I hiked it once at 2 p.m. in August, and the afternoon heat was intense. Start early, and bring more water than you think you will need.

🟡 Wear sturdy shoes. Skip the sandals and leave the dog home. No motorized vehicles or e-bikes on the trail.

Collecting Obsidian

Rock collecting is prohibited within Newberry National Volcanic Monument. Look, photograph, and leave it alone.

Enjoy the views, take photos, and leave the landscape as you found it.

If you want to legally collect obsidian, drive to Glass Buttes, about 80 miles east near Highway 20. This area is open to hobby collecting and is known for colorful varieties, including rainbow, mahogany, snowflake, midnight lace, and double-flow obsidian.

Come to Newberry for the geology. Go to Glass Buttes if you want to collect.

You can easily build a full weekend around Newberry Volcano. Paulina Falls drops about 80 feet in a spectacular twin cascade just a few miles away, with short walks leading to both the upper and lower viewpoints.

Paulina Lake Hot Springs and East Lake Hot Springs sit along shorelines of two neighboring lakes, where geothermal water seeps up through the gravel. Those lakes are also popular with anglers, who fish for rainbow trout, brown trout, and kokanee.

Beyond the caldera, Lava River Cave extends about a mile underground and is Oregon's longest lava tube.

Other nearby attractions include Lava Cast Forest, Fort Rock State Natural Area, Crack-In-The-Ground, Hole in the Ground, and Pilot Butte.

Several Forest Service campgrounds sit right inside the caldera, which makes camping the easy call.

Paulina Lake Campground and Little Crater Campground put you within a few minutes of the trailhead, and Little Crater is the largest in the monument with well over 100 sites.

East Lake Campground and Cinder Hill Campground sit on the other side of the water.

Most close by mid-October, and many fill fast on summer weekends. Reserve early if you can.

Prefer a hot shower? La Pine is the closest town at 21 miles west. Bend offers far more hotels, restaurants, and gear shops.

Lodging in Bend