The Cascade–Siskiyou National Monument is a United States national monument that protects 114,000 acres (46,134 ha)[1] of forest and grasslands at the junction of the Cascade Range and the Siskiyou Mountains in Southwestern Oregon and Northwestern California, United States.

Nearly 100 dwelling and root-gathering sites belonging to the Modoc, Klamath, and Shasta tribes have been uncovered to date.

[6][7] Natural features in the monument include Pilot Rock, a volcanic neck or interior of an extinct volcano, similarly formed as Devils Tower in Wyoming, and the Soda Mountain Wilderness.

There is a fire lookout tower on the top of Soda Mountain built in 1962 to replace the original 1933 structure.

[16] Federal judges in Washington, DC and Oregon issued conflicting decisions in 2019 over the legality of the expansion into O&C Lands.

The range of elevations and diversity of habitat types provides for a spectacular flora that includes many endemics to the immediate Siskiyou crest area, such as Green's mariposa lily (Calochortus greenei).