Mount Defiance is a peak near the

Columbia River Gorge The Columbia River Gorge is a canyon of the Columbia River in the Pacific Northwest of the United States. Up to deep, the canyon stretches for over as the river winds westward through the Cascade Range, forming the boundary between the sta ...

in the US state of

Oregon Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of it ...

. It rises to an elevation of in the

Mount Hood National Forest The Mount Hood National Forest is a U.S. National Forest in the U.S. state of Oregon, located east of the city of Portland and the northern Willamette River valley. The Forest extends south from the Columbia River Gorge across more than of fore ...

Hood River County, Oregon Hood River County is one of the 36 counties in the U.S. state of Oregon. As of the 2020 census, the population was 23,977. The county seat is Hood River. The county was established in 1908 and is named for the Hood River, a tributary of th ...

. The northern and western flanks of the mountain are in the

Mark O. Hatfield Wilderness The Mark O. Hatfield Wilderness is a wilderness area located on the northern side of Mount Hood in the northwestern Cascades of the U.S. state of Oregon, near the Columbia River Gorge and within Mount Hood National Forest. Prior to Wilderness des ...

. The route up the mountain is often considered one of the hardest climbs in the Gorge; the trail gains in from the Starvation Creek Trailhead. Mount Defiance is composed chiefly of

lava flows Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or un ...

. The base is

basalt Basalt (; ) is an aphanite, aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the planetary surface, surface of a terrestrial ...

from an old

shield volcano A shield volcano is a type of volcano named for its low profile, resembling a warrior's shield lying on the ground. It is formed by the eruption of highly fluid (low viscosity) lava, which travels farther and forms thinner flows than the more v ...

, and it is capped by

andesite Andesite () is a volcanic rock of intermediate composition. In a general sense, it is the intermediate type between silica-poor basalt and silica-rich rhyolite. It is fine-grained (aphanitic) to porphyritic in texture, and is composed predomi ...

. The mountain was named by Dr. P.G. Barrett, an early resident of

Hood River Valley Hood River Valley is the river basin of Hood River in northern Oregon, U.S. It is bounded by the Columbia River to the north, Mount Hood to the south, the Cascade Range crest to the west and an apparently unnamed ridge system to the east which c ...

, as he believed it retained its winter snow late into the spring in defiance of the warming weather.

References

External links

* * {{DEFAULTSORT:Defiance Mountains of Oregon Landforms of Hood River County, Oregon Volcanoes of Oregon Volcanoes of the United States Cascade Volcanoes