It is in the semi-arid, sparsely-populated northeastern corner of California and the south-central portion of Oregon.

The Fandango Pass in the Warner Mountains was on the Lassen-Applegate Trail used by emigrants from 1846 to 1850 as an alternate route to the Willamette Valley in Oregon and the gold fields of California.

[4] Great quantities of lumber were removed from the Warner Mountains beginning as early as 1920.

The sawmill and box factory at Willow Ranch near the Oregon–California border was a company town with a population over 1,000 during the 1930s and 1940s.

The range was named after explorer Captain William H. Warner, of the U.S. Army Corps of Topographical Engineers, who was killed in the range by Native Americans on September 26, 1849, while exploring a route for potential railroad crossings of the Sierra Nevada.