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Geologic sightseeing

Learn more about Oregon's geology

Cascade Mountains

The Cascade province is actually made up of two volcanic regions, the older, broader, and deeply eroded Western Cascades and the dominating, snow-capped peaks of the younger, more easterly volcanoes of the High Cascades, such as Mount Hood, Mount Jefferson, and the Three Sisters (North, Middle, and South Sister). Another High Cascade peak, Mount Mazama, was destroyed about 6,800 years ago by a catastrophic eruption that left a deep caldera later filled by what is now Crater Lake.

Mount Hood Loop,
located on the northern boundary of Oregon: One of the world’s most scenic highway loops, through a gorge cut by the Columbia River along Interstate I-84, along the fault-and volcano-bounded Hood River Valley (Hwy. 35), and up the flanks of Mount Hood (Highways 35 and 26). For information, contact Columbia River Gorge National Scenic Area, 902 Wasco Ave., Suite 200, Hood River, OR 97031, phone 541-386-2333, or Mt. Hood National Forest, 16400 Champion Way, Sandy OR 97053, phone 503-668-1700.

McKenzie Pass Highway,
crossing the Cascades along Hwys. 242 and 126 between Sisters and Eugene: A view of volcanoes, lava flows, cinder cones, and the Dee Wright Volcano Observatory.

Crater Lake National Park,

located in southwest Oregon, with year-round access on the south via Hwy. 62: World-famous, 1,900-foot-deep Crater Lake lies in the caldera of what is left of once 12,000-foot -high-Mt. Mazama, which was destroyed by a catastrophic eruption about 6,800 years ago. For information, contact superintendent, Crater Lake National Park, Box 7, Crater Lake, OR 97604, 541-594-2211

Oregon Outdoors
The Cascades Volcano Observatory

Mount Hood National Forest
Willamette National Forest
Deschutes and Ochoco National Forests
Umpqua National Forest
Winema National Forest

Virtual Cascades Tour
Crater Lake National Park

map legendCoastal RangeKlamath MountainsDeschutes-Columbia PlateauBlue MountainsHigh Lava PlainsCascade RangeWillamette ValleyBasin & Range & Owyhee uplandsBasin & Range & Owyhee uplands

Graphic by Elizabeth L. Orr, Geology of Oregon

map legendaBlue MountainsWillamette ValleyDeschutes-Columbia plateauKlamath MountainsCoast Rangemap legendbCascade MountainsBasin Range & Owyhee uplandsHigh Lava plainsOwyhee UplandsCascade MountainsBasin & Range & Owyhee UplandsHigh Lava PlainsOwyhee UplandsCascade MountainsBasin & Range & Owyhee UplandsHigh Lava PlainsOwyhee UplandsCascade MountainsBasin & Range & Owyhee UplandsHigh Lava PlainsOwyhee UplandsCascade MountainsBasin & Range & Owyhee UplandsHigh Lava PlainsOwyhee Uplands

back to Geology sightseeing

Broken Top
Broken Top near Bend

Trillium Lake
Trillium Lake and Mount Hood
near Portland

Crater lake
Crater Lake National Park
in southern Oregon

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Oregon Department of Geology and Mineral Industries
800 NE Oregon Street, Suite 965, Portland, OR 97232-2162
971-673-1555, FAX 971-673-1562
email us at DOGAMI