Siskiyou Mountains

The Siskiyou Mountains are a mountain range straddling the border region of northern California and southwestern Oregon in the western United States, forming part of the greater Klamath Mountains complex. The range is known for complex geology and unusually high plant diversity, including many endemic species.

Trails, forest roads and wilderness areas provide access for hiking, wildlife viewing and backcountry recreation; the region contains varied habitats from low-elevation mixed conifer forest to high-elevation ridgelines. The mountains are also noted for serpentine-derived soils that support specialized plant communities.

Geographically the Siskiyous run across the Oregon-California border and form a transitional zone between coastal ranges and inland plateaus, with a mix of steep ridges, deep river valleys and isolated high peaks.

• Geology and biodiversity: Part of the Klamath-Siskiyou region noted for botanical diversity and complex geology, including ancient metamorphic and serpentinite rocks.
• Extent and elevation: Range spans northern California and southern Oregon with summits and ridges reaching well above 2,000 metres in places.