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 state ...

in the US state of

Oregon Oregon ( , ) is a U.S. state, state in the Pacific Northwest region of the United States. It is a part of the Western U.S., with the Columbia River delineating much of Oregon's northern boundary with Washington (state), Washington, while t ...

. 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 The Willamette River ( ) is a major tributary of the Columbia River, accounting fo ...

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 t ...

. The northern and western flanks of the mountain are in the Mark O. Hatfield Wilderness. 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 unde ...

. 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 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 viscous lava ...

, 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 predomina ...

. The mountain was named by Dr. P.G. Barrett, an early resident of the Hood River Valley, 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 Cascade Volcanoes