Oregon has roughly 22 major volcanic centers stretching from the snow-capped Cascade peaks to the basalt lava fields of the high desert. Four are rated "very high threat" by the USGS. The state's volcanoes include Crater Lake's VEI 7 caldera, the deepest lake in the US, and Mount Hood, the volcano most likely to erupt next in the Pacific Northwest after Mount St. Helens.
In Our Database
~20
USGS Very High Threat
4
Last Erupted
~1866
Deepest Lake (US)
594 m
Why Does Oregon Have Volcanoes?
The Juan de Fuca Plate — a small oceanic plate off the Pacific Northwest coast — is diving beneath the North American Plate at roughly 4 cm per year. As it descends into the mantle, water released from the sinking plate lowers the melting point of the overlying rock, generating magma that rises to the surface along the Cascade Volcanic Arc. This process, called subduction, built every major Cascade peak from Mount Lassen in California to Mount Baker in Washington — including Oregon's Hood, Jefferson, Three Sisters, and Crater Lake.
But the Cascades don't tell the whole story. Eastern Oregon sits within the Basin and Range province, where the Earth's crust is being stretched and thinned. This extension has produced a second volcanic zone — one characterized by shield volcanoes, basalt lava flows, and lava fields like Diamond Craters and Jordan Craters. Some geologists also connect eastern Oregon's volcanism to the passage of the Yellowstone hotspot track, which crossed this region millions of years ago.
By VolcanoDB Research Team. Data: USGS Cascades Volcano Observatory, Smithsonian Global Volcanism Program.
Major Oregon Volcanoes
Oregon's volcanic roster ranges from towering stratovolcanoes with glaciated summits to small cinder cone fields and maar craters in the high desert. Here are the ten most significant, each linked to its full database page with eruption records, coordinates, and monitoring data.
These are the Oregon volcanoes that keep USGS geologists up at night — or draw millions of visitors a year. Each tells a different story about how volcanism shapes the Pacific Northwest.
Oregon's tallest peak and the volcano most likely to erupt next in the state. Hood last erupted around 1781-1866, producing pyroclastic flows, lava domes, and lahars that traveled down river valleys toward the Columbia River. The USGS ranks it #6 on the national Very High Threat list — ahead of every Cascade volcano except Mount St. Helens, Rainier, and a few others.
Despite the hazard, Hood is the most climbed glaciated peak in North America. About 10,000 people attempt the summit each year, and Timberline Lodge on its south flank offers the only year-round skiing in North America. The USGS operates a lahar detection system on Hood's flanks because a future eruption would almost certainly send mudflows down the Sandy, Zigzag, and White River drainages — some of which lead toward populated areas in the greater Portland region.
Around 7,700 years ago, Mount Mazama erupted in a VEI 7 event — one of the largest volcanic eruptions on Earth in the last 12,000 years. Roughly 50 cubic kilometers of magma blasted out, and the mountain collapsed into the emptied chamber. The resulting caldera slowly filled with centuries of rain and snowmelt to form the deepest lake in the United States: 594 meters (1,949 feet). No rivers flow in or out. The water is almost impossibly blue.
Wizard Island, a cinder cone rising above the lake's surface, proves volcanism didn't stop with the collapse — smaller eruptions continued within the caldera for thousands of years. Crater Lake became a National Park in 1902, Oregon's only national park. The Klamath people witnessed the eruption; their oral histories describe a battle between the sky god Skell and the underworld god Llao that matches the geological record remarkably well.
Three aligned stratovolcanoes — North, Middle, and South Sister — dominate the central Oregon Cascades. North Sister is the oldest and most eroded, built mostly of basaltic andesite over 55,000 years ago. Middle Sister sits between its siblings and last erupted about 14,000 years ago. South Sister is the youngest and tallest at 3,157 meters, with its most recent eruption about 2,000 years ago producing rhyolite lava flows.
The real reason USGS watches Three Sisters closely: satellite radar detected ground uplift about 5 km west of South Sister starting in 1998. By 2024, the surface had risen approximately 30 cm — indicating magma or magmatic fluids accumulating at depth. The rate has fluctuated but hasn't stopped. This doesn't mean an eruption is imminent. But it does mean something is happening underground, and the USGS Cascades Volcano Observatory is monitoring it with GPS, seismometers, and satellite data.
Newberry is one of the largest volcanoes in the Cascades by area — its shield base stretches over 1,600 square kilometers, wider than any Cascade stratovolcano. The summit caldera holds two lakes — Paulina Lake and East Lake — separated by a ridge. Hot springs warm the shores of both, evidence of the heat still present at depth.
The Big Obsidian Flow, dating to approximately 1,300 years ago, is one of the youngest lava flows in Oregon. It's a massive pile of black volcanic glass — you can walk across it on a short trail and watch it glitter in the sunlight. Newberry has erupted at least 25 times in the last 12,000 years. The USGS ranks it #13 on the national Very High Threat list, partly because the city of Bend (population ~100,000) sits directly on its northwest flank. For a comparison of large shield volcanoes with summit calderas, see our Yellowstone volcano page.
Oregon's second-tallest peak at 3,199 meters is also one of its least-monitored major volcanoes. Jefferson is heavily glaciated, with five named glaciers carving into its steep flanks. It last erupted about 4,500 years ago, producing ash and pyroclastic flows. The mountain sits within the Mount Jefferson Wilderness and the Warm Springs Indian Reservation — access is more limited than Hood or the Sisters.
Jefferson receives less attention than its neighbors, but the hazard is real. A future eruption could send lahars down the Whitewater, Jefferson, and Milk Creek drainages. The USGS classifies it as "High Threat" rather than "Very High" largely because of the lower surrounding population. But the mountain deserves more monitoring infrastructure than it currently has.
Eastern Oregon's Volcanic Fields
East of the Cascades, Oregon's high desert holds a completely different style of volcanism. Where the Cascades produce explosive stratovolcanoes, the Basin and Range province generates low-profile basalt lava flows, cinder cone chains, and maar craters. The geology is related to crustal extension — the land is literally being pulled apart — rather than subduction.
Diamond Craters(ID 1023) is a textbook example: a compact volcanic field in Harney County with maars, lava flows, domes, and craters all within a few square kilometers. The BLM calls it "a volcanic museum." Jordan Craters(ID 1025) near the Idaho border has remarkably fresh pahoehoe lava flows — so well-preserved they look like they could have erupted last century, though they're about 3,000 years old. Four Craters Lava Field (ID 1019) in the Christmas Valley area offers a chain of cinder cones and a massive lava flow visible from space.
Newberry's lava tubes also deserve mention here. Lava River Cave, at 1.6 km, is the longest lava tube in Oregon. These tubes formed when the surface of a lava flow cooled and hardened while molten lava continued flowing underneath, eventually draining out and leaving a hollow tunnel. They're impressive and accessible — and a great way to experience volcanic geology without climbing anything.
Visiting Oregon's Volcanoes
Oregon has some of the best volcanic tourism in the contiguous US. Crater Lake alone draws about 700,000 visitors a year, and Mount Hood's Timberline Lodge is a year-round destination. But the real gems are the less-visited spots — Newberry's obsidian flow, the lava tubes south of Bend, and the wild volcanic landscapes of the Three Sisters Wilderness. For a broader guide, see our volcano hiking guide.
Crater Lake National Park
The deepest lake in the United States at 594 meters fills the caldera left by Mount Mazama's VEI 7 eruption ~7,700 years ago. The 53 km Rim Drive circles the entire caldera with dozens of overlooks. Boat tours to Wizard Island run June through mid-September. I've stood on the rim in every season — winter, when 12 meters of snow blankets everything and only the south entrance is open, is the most dramatic. The water is impossibly blue because it's fed entirely by rain and snowmelt with almost zero sediment.
$35/vehicle (7-day pass), $55 annualBest: Rim Drive open late June to mid-October. Park open year-round (south entrance only in winter).View in database →
Mount Hood — Timberline Lodge & Climbing
Oregon's tallest peak has year-round skiing at Timberline Lodge (the only place in North America where you can ski 12 months a year). The historic lodge, built by the WPA in 1937, served as the exterior of the Overlook Hotel in The Shining. Climbing permits are required May through June for routes above 10,000 feet. The south side route is non-technical but demands crampons and ice axe — around 10,000 people attempt the summit each year, making Hood the most-climbed glaciated peak in North America.
Climbing permits ~$20/person (May-June). Timberline lift tickets ~$89-119.Best: Summit attempts: May-June. Skiing: year-round at Timberline. Hiking: July-October.View in database →
Three Sisters Wilderness
290,000 acres of alpine wilderness surrounding all three Sister volcanoes. The most popular backpacking loop circles South Sister with views of broken lava fields, glacial lakes, and all three peaks. Day-hiking to South Sister's summit (3,157m) is a steep but non-technical 18 km round trip. The Obsidian Trail passes through ancient obsidian flows — you'll crunch over black volcanic glass. Limited-entry permits required for popular trailheads from late May through September.
Free (wilderness). Limited-entry trailhead permits required at some access points.Best: Late July to early October. Snow lingers into July at higher elevations.View in database →
Newberry National Volcanic Monument
Managed by the Forest Service, not the Park Service, which keeps crowds lower than you'd expect for something this good. The Big Obsidian Flow trail is a 1.6 km loop across a massive obsidian lava flow that's only ~1,300 years old — the black glass glitters in the sun. The caldera holds two lakes (Paulina Lake and East Lake) with fishing and hot springs. Paulina Falls drops 24 meters at the caldera's western rim. This is the most underrated volcanic site in Oregon. If you visit one lesser-known spot, make it this one.
$5/vehicle day pass. $30 Northwest Forest Pass annual.Best: June through October. Roads close in winter.View in database →
Lava River Cave
Oregon's longest lava tube stretches 1.6 km under the high desert south of Bend. You walk through a tube formed by a basaltic lava flow about 80,000 years ago — the ceiling drips with lava stalactites and the temperature holds at about 4 degrees Celsius year-round (bring layers). Lantern rentals available at the entrance. It's dark, uneven, and genuinely thrilling for kids and adults. Part of Newberry's broader volcanic system.
$5/vehicle. Lantern rental $5.Best: May through mid-October (closed in winter for bat hibernation).View in database →
One more thing: if you're visiting the Cascades, don't skip Washington's volcanoes just across the Columbia River. Mount St. Helens is only a few hours from Portland, and the 1980 eruption blast zone is one of the most dramatic volcanic landscapes in the world. Mount Adams and Rainier are further north but worth the drive.
Explore All Oregon Volcanoes in Our Database
Every Oregon volcano with eruption history, USGS threat level, coordinates, and geological data
Oregon has approximately 22 major volcanic centers tracked in databases like ours and the Smithsonian GVP. These range from massive stratovolcanoes like Mount Hood (3,429m) to small cinder cones and lava fields in the high desert of eastern Oregon. The Cascade Range accounts for the major peaks, while the Basin and Range province in southeast Oregon contains additional lava fields like Diamond Craters and Jordan Craters. If you count every individual vent and cinder cone, the total reaches into the hundreds.
Are there any active volcanoes in Oregon?
Yes. The USGS classifies several Oregon volcanoes as active based on Holocene eruption records and current monitoring data. Mount Hood last erupted around 1866. South Sister has shown ground uplift of approximately 30 cm since 1998, indicating magma movement at depth. Newberry Volcano's Big Obsidian Flow is only about 1,300 years old. The USGS rates four Oregon volcanoes as 'very high threat': Hood, Crater Lake, Three Sisters, and Newberry. The Cascades Volcano Observatory in Vancouver, Washington monitors all of them continuously.
Could Mount Hood erupt?
Yes, and the USGS considers it the Oregon volcano most likely to erupt next. Hood is ranked #6 on the national Very High Threat list. It has had two major eruptive periods in the last 1,800 years — the Old Maid period (~1,500 years ago, with pyroclastic flows and lahars) and the most recent activity around 1781-1866. An eruption would likely produce lahars (volcanic mudflows) flowing down the Sandy and White Rivers toward the Portland metro area. The USGS operates a lahar detection system on Hood's flanks. An eruption is not imminent, but Hood will erupt again.
Is Crater Lake a volcano?
Crater Lake fills the caldera of Mount Mazama, which erupted catastrophically about 7,700 years ago in a VEI 7 event — one of the largest eruptions on Earth in the last 12,000 years. The eruption ejected approximately 50 cubic kilometers of material, and the mountain collapsed into the emptied magma chamber. The caldera filled with rain and snowmelt over centuries to form the deepest lake in the US (594m / 1,949 ft). Wizard Island, a cinder cone rising from the lake, proves that volcanic activity continued after the caldera formed. Crater Lake is considered active — there have been smaller eruptions within the caldera in the last 5,000 years.
What is the tallest volcano in Oregon?
Mount Hood at 3,429 meters (11,250 feet) is the tallest volcano and the highest point in Oregon. It's followed by Mount Jefferson at 3,199m, South Sister at 3,157m, and North Sister at 3,074m — all Cascade Range stratovolcanoes. Hood is also the most climbed glaciated peak in North America, with roughly 10,000 summit attempts per year.