Three Fingered Jack

Three Fingered Jack
Southwest side of Three Fingered Jack seen from Pacific Crest Trail
Highest point
Elevation	7,844 ft (2,391 m) NAVD 88[1]
Coordinates	44°28′44″N 121°50′35″W / 44.478965122°N 121.843058797°W / 44.478965122; -121.843058797[1]
Geography
Three Fingered Jack Jefferson and Linn counties, Oregon, U.S.[2] Show map of the United States Three Fingered Jack Three Fingered Jack (Oregon) Show map of Oregon
Parent range	Cascades
Topo map	USGS Three Fingered Jack
Geology
Age of rock	older than 200,000 years
Mountain type	Summit, Shield volcano
Volcanic arc	Cascade Volcanic Arc
Last eruption	Pleistocene
Climbing
First ascent	1923 by E. McNeal and party[3]

Three Fingered Jack is a summit of a shield volcano of the Cascade Range in the U.S. state of Oregon. Formed during the Pleistocene epoch, the mountain consists mainly of basaltic andesite lava and was heavily glaciated in the past. While other Oregon volcanoes that were heavily glaciated—such as Mount Washington and Mount Thielsen—display eroded volcanic necks, Three Fingered Jack's present summit is a comparatively narrow ridge of loose tephra supported by a dike only 10 feet (3.0 m) thick on a generally north–south axis. Glaciation exposed radiating dikes and plugs that support this summit. The volcano has long been inactive and is highly eroded.

Three Fingered Jack has diverse flora, fauna, and fungi. The Molala people, one of the indigenous groups in the northwestern United States, historically inhabited the area around the volcano. Not much is known about Molala culture, other than that the group fished for salmon and collected berries, fruits, obsidian, and dried herbs. David Douglas was the first person of non-indigenous descent to reach the area in 1825, followed by Peter Skene Ogden the following year. The first group to ascend the volcano reached its summit in September 1923. Three Fingered Jack can still be climbed, but climbers can require rescue after becoming disoriented in low visibility conditions.