Arnica viscosa is an uncommon North American species of arnica in the sunflower family, known by the common name Mount Shasta arnica (not to be confused with the Shasta County arnica, A. venosa). It is native to the Klamath Mountains and nearby southern Cascade Range in northern California (Shasta, Siskiyou and Trinity Counties) and southern Oregon (Josephine, Douglas, Klamath, and Deschutes Counties). It grows in subalpine to alpine habitats.