Siskiyu is a monotypic genus of spiders in the family Cybaeidae containing the single species, Siskiyu armilla.
Siskiyu armilla has been recorded from northern California and southern Oregon.
The genus is named after the Klamath-Siskiyou Mountains that encompass much of the known distribution of this genus. The specific name is from Latin "armilla" (ring, bracelet), referring to the conspicuous ring-like patellar fracture lines.