Quartz Mountain is a 5,200-foot peak in Oregon's Umpqua National Forest, about 35 miles east of Roseburg in Douglas County. Located in the Jackson Creek subbasin within the South Umpqua River watershed, it is distinguished by a large deposit of high-purity silica that gave the mountain its name. Its summit formerly supported a Forest Service lookout tower that served the region's fire-detection system until the tower was removed in 1970. Quartz Mountain remains a recognized summit in the forested uplands of southwestern Oregon.