The Cascade–Siskiyou National Monument is a United States national monument that protects 114,000 acres (46,134 ha) of forest and grasslands at the junction of the Cascade Range and the Siskiyou Mountains in Southwestern Oregon and Northwestern California, United States. The monument is managed by the Bureau of Land Management as part of the National Landscape Conservation System. It was established in a presidential proclamation by President Bill Clinton on June 9, 2000 and expanded by President Barack Obama on January 12, 2017.