Hager Mountain is a volcanic peak in south-central Oregon on the northwestern edge of the Basin and Range Province, where pine forest gives way to high desert. Rising to 7,189 feet, it is a large silicic lava dome formed about 5.9 million years ago, with basalt, andesite, pumice, and obsidian across its slopes. Known to the Northern Paiute and Klamath long before Euro-American settlement, it was later renamed for a Silver Lake Valley rancher. Since 1915, the summit has served as a fire lookout site; the present 1954 lookout also anchors a popular hiking destination with expansive views across Lake County and distant Cascade peaks.