The Warner Mountains drop steeply on the eastern slopes, whereas the western flank has a more gentle topography.

Due to the elevation and precipitation differences, the forests hosts a large number of plant species.

The western side of the brushy foothills consist mostly of bitterbrush and curl-leaf mahogany.

As elevation increases, forests of ponderosa pine, white and red firs, incense cedar, and aspen give way to lodgepole and western white pines sprinkle towards the summit.

There are local ranger district offices located in Adin, Alturas, Cedarville, and Tulelake.