Oregon’s landforms run from volcanic peaks to sea level: the Cascade Range with Mount Hood, the state’s highest point at 3,429 m (11,249 ft); the fault-block mountains and dry lake beds of the High Desert; Crater Lake, the deepest lake in the United States at 594 m (1,949 ft); Hells Canyon, North America’s deepest river gorge; the Willamette Valley; the Columbia River Gorge; and the Coast Range and Pacific shore, where the state bottoms out at sea level. Geographers divide its 254,810 km² (98,381 sq mi) into eight regions: the Oregon Coast, Willamette Valley, Rogue Valley, Cascade Range and Klamath Mountains in the west, and the Columbia Plateau, High Desert and Blue Mountains in the centre and east. The mean elevation is about 1,006 m (3,300 ft). The simplest way to see how they fit together is to start at the top and walk downhill.
Mount Hood, 3,429 m: Oregon’s Summit
Mount Hood rises about 80 km (50 mi) east-southeast of Portland, on the line between Clackamas and Hood River counties. It is a stratovolcano of the Cascade Volcanic Arc, built by the subduction of the Juan de Fuca Plate beneath North America, and at 3,429 m (11,249 ft) it is the fourth-highest peak in the Cascades. Twelve named glaciers and snowfields cover its upper slopes. The US Geological Survey puts the odds of an eruption in the next 30 years at 3 to 7 percent and classes it as potentially active; it is the Oregon volcano considered most likely to erupt.
The mountain is also Oregon’s busiest high ground. About 10,000 climbers attempt it each year, and the Timberline ski area on its south flank, with a lift base near 2,120 m (6,940 ft), offers the only year-round lift-served skiing in North America. Timberline Lodge, a National Historic Landmark, stands at about 1,800 m (6,000 ft) just below the Palmer Glacier.
The Three Sisters, Each Above 3,000 m
South along the Cascade crest, past Mount Jefferson, the second-highest mountain in Oregon, the next rungs down are the Three Sisters, a cluster of closely spaced volcanoes about 16 km (10 mi) south of the town of Sisters, on the boundary of Lane and Deschutes counties. Each tops 3,000 m (10,000 ft), and together they are the third-, fourth- and fifth-highest peaks in Oregon; North Sister reaches 3,075 m (10,090 ft). Their snowfields and glaciers range from about 2,055 to 3,142 m in altitude.
The Cascade crest also divides Oregon in two. West of it, moist Pacific air feeds dense forest: around 80 percent of the land west of the Cascades is wooded, and Oregon is the top timber producer in the lower 48 states. East of it, in the lee of the mountains, the country opens into juniper, sagebrush and the volcanic rock of Central Oregon, including the lava beds of the Oregon Badlands Wilderness.
Steens Mountain, 2,968 m, and the Alvord Desert Below
In Harney County in the southeast, far from the Cascades, the land rises again. Steens Mountain is a single fault-block mountain about 80 km (50 mi) long, the largest of Oregon’s fault-block mountains, rising to 2,968 m (9,738 ft). It is a horst, a raised block of crust, built from flood basalts: more than forty lava flows, erupted between about 17 and 14 million years ago, are stacked in its eastern face, reaching 910 m (3,000 ft) thick or more in places. Movement on the Steens Mountain Fault, mostly between 12 and 10 million years ago, then lowered the basin at its eastern foot.
The drop is spectacular. The Alvord Desert, a dry lake bed at the eastern foot of the mountain, lies at about 1,280 m (4,200 ft), so the eastern escarpment climbs more than 1,600 m in a short distance. Streams run onto the playa but the basin has no outlet, so the water evaporates and leaves salts behind. Dry for much of the year, its flat surface is used for land sailing and glider flying, and researchers have tested Mars exploration sensors there. More than 91 km² of the playa lie within the Alvord Desert Wilderness Study Area. The Wadatika, a Northern Paiute band, spent part of late summer and early autumn here and wintered near Malheur Lake.
Crater Lake, a Mountain Turned Upside Down
Back in the southern Cascades, in Klamath County, stood Mount Mazama, a volcano that reached roughly 3,700 m (12,000 ft). About 7,700 years ago a climactic eruption emptied the magma chamber beneath it and the summit collapsed, lowering the mountain to 2,486 m (8,157 ft) and leaving a caldera about 655 m (2,148 ft) deep. Rain and snow slowly filled it to make Crater Lake. Artifacts including sandals found under the eruption’s ash show that people lived here before the collapse, and the lake remains significant to the Klamath Tribes, who call it Giiwas.
The lake is about 8 by 9.7 km (5 by 6 mi) across, ringed by a rim between 2,100 and 2,400 m (7,000 to 8,000 ft) high. It reaches 594 m (1,949 ft) at its deepest and averages 350 m (1,148 ft), which makes it the deepest lake in the United States. No rivers flow in or out; rain and snow balance evaporation so that the water is replaced roughly every 150 years. Two islands break the surface: Wizard Island, a cinder cone of about 128 hectares near the western shore, and the Phantom Ship, a rock pillar near the southern shore. The lake is the centrepiece of Oregon’s only national park, described in our Crater Lake National Park guide.
Hells Canyon, 2,436 m Deep on the Snake River
On the northeastern border the land does not descend gently; it falls into a trench. Hells Canyon, cut by the Snake River along the Oregon–Idaho line with a short stretch in Washington, is about 16 km (10 mi) wide and 2,436 m (7,993 ft) deep, making it the deepest river gorge in North America, deeper than the Grand Canyon. The river runs more than 1.6 km (1 mi) below the western rim on the Oregon side and 2,260 m (7,400 ft) below the peaks of Idaho’s Seven Devils Mountains.
The rocks record a long history. About 300 million years ago an arc of volcanoes rose from the Pacific; between 130 and 17 million years ago the ocean plate carrying them collided with North America and was welded onto it. Floods of basalt lava then covered the region and smoothed it into a high plateau, and rivers began carving Hells Canyon into it, about 6 million years ago on the usual estimate, though a 2025 study argues the canyon is younger, begun only 1.6 million years ago. Much of its 870 km² of wilderness cannot be reached by road.
The Willamette Valley, Where the Oregon Trail Ended
West of the Cascades lies the lowland that holds most Oregonians. The Willamette Valley is about 240 km (150 mi) long, enclosed by the Cascades to the east, the Coast Range to the west and the Calapooya Mountains to the south, with the Willamette River running its full length. Roughly 70 percent of the state’s people live here, including the five largest cities: Portland, Eugene, Salem, Gresham and Hillsboro.
Much of its fertility is a gift of the Ice Age. The Missoula Floods, released each time the ice dam holding back Glacial Lake Missoula in Montana ruptured, swept topsoil from Eastern Washington down the Columbia. Where the water met ice and log jams at Kalama in Washington it backed up, filling the valley to 91 to 122 m (300 to 400 ft) above today’s sea level about 40 times between 15,000 and 13,000 years ago. In the 1820s the valley was publicised as a promised land of milk and honey, and through the 19th century it was the destination of choice for wagon trains on the Oregon Trail. Today it holds more than 7,700 hectares of vineyards and over 500 wineries.
The Columbia River Gorge, a Sea-Level Gap Through the Cascades
The Columbia forms much of Oregon’s northern border and is one of only four rivers, with the Klamath, the Pit and the Fraser, that connect the land east of the Cascades to the Pacific. The Columbia River Gorge stretches more than 130 km (80 mi) from around the mouth of the Deschutes River to the eastern edge of the Portland area, with walls up to 1,200 m (4,000 ft) high. It is the only navigable route through the Cascades, so Interstate 84, US Route 30 and railways on both banks all squeeze through it.
Within those 130 km, precipitation falls from about 2,500 mm (100 in) a year at the western end to only 250 mm (10 in) at the eastern end, so temperate rainforest gives way to grassland. Side streams leap off the basalt cliffs; Multnomah Falls, in two tiers, is the tallest waterfall in Oregon at 189 m (620 ft). Our Columbia River Gorge guide covers its waterfalls and viewpoints in more detail.
Haystack Rock and the Pacific Shore at Sea Level
The last range before the ocean is the Coast Range, whose highest summit is Marys Peak, just southwest of Philomath in Benton County. Beyond it, the Oregon Coast is the state’s lowest ground: the Pacific at sea level.
Waves have carved the shore into headlands, coves and sea stacks. At Cannon Beach, Haystack Rock rises 72 m (235 ft) from the sand, a basalt monolith, formed by lava flows 15 to 17 million years ago, that can be reached on foot at low tide; its tide pools hold starfish, anemones and crabs, and puffins and terns nest on it. It has been protected as a marine garden since 1990. Further south, between Florence on the Siuslaw River and North Bend on the Coos River, the Oregon Dunes stretch about 64 km (40 mi), the largest expanse of coastal sand dunes in North America, with some dunes rising 150 m (500 ft) above the sea. At Lincoln City, the D River, about 130 m (440 ft) long, once held the Guinness record as the world’s shortest river; Guinness gave the title to Montana’s Roe River in 1989, and the dispute that followed ran until Guinness stopped listing the category in 2006.
This shoreline sits above the Cascadia subduction zone, the same plate boundary that feeds Mount Hood; its last great earthquake struck in January 1700. From Hood’s summit to the surf is a fall of 3,429 m, and the volcanoes that make up the top rungs of that descent continue north into Washington, as our Cascade Range mountain guide shows.