Mount Defiance is a prominent mountain near the Columbia River Gorge in northern Oregon, in the Mount Hood National Forest, with its northern and western sides extending into the Mark O. Hatfield Wilderness. The peak stands out both for its protected setting and for the volcanic forces that formed it: basalt from an older shield volcano makes up its base, while andesite caps the summit. It is also widely known for an exceptionally strenuous hike, rising about 5,000 feet in 6 miles from Starvation Creek. Early Hood River Valley resident Dr. P.G. Barrett named it for snow that lingered late into spring.