The Siskiyou Mountains are a coastal mountain range in the northern Klamath Mountains in northwestern California and southwestern Oregon in the United States. They extend in an arc for approximately 100 mi (160 km) from east of Crescent City, California northeast along the north side of the Klamath River into Josephine and Jackson counties in Oregon. The mountain range forms a barrier between the watersheds of the Klamath River to the south and the Rogue River to the north.
The highest peaks in the range include Mt. Ashland (elevation 7,533 ft/2,296 m), Dutchman Peak (7,410 ft/2,259 m), Siskiyou Peak (7,147 ft/2,178 m) and Wagner Butte (7,140 ft/2,176 m) all of which are in Oregon. The highest peak in the California portion of the range is Preston Peak (7,309 ft/2,228 m). Due to this high elevation and proximity to the Pacific Ocean, the peaks get high precipitation (rainfall and snowfall) and thus its forests are a lush green.
Much of the range is embraced by the Rogue River, Klamath, and Siskiyou National Forests. The Pacific Crest Trail follows a portion of the ridge of the range. The Klamath-Siskiyou forests are noted for their high biodiversity.
The origin of the word siskiyou is not known. One version is that it is the Chinook Jargon word for "bob-tailed horse." According to historian Richard Mackie, "Siskiyou" was a Cree word for a bob-tailed horse, one of which perished in 1829 during Alexander McLeod's journey over a pass later named for the "siskiyou" (today's Siskiyou Pass). The Cree were in the area as part of McLeod's Hudson's Bay Company expedition, and had been recruited far away in their homeland in eastern Canada. Another version, given in an argument before the State Senate in 1852, is that the French name Six Cailloux, meaning "six-stones," was given to a ford on the Umpqua River by Michel Laframboise and a party of Hudson's Bay Company company trappers in 1832, because six large stones or rocks lay in the river where they crossed. According to some, the Six Cailloux name was appropriated to this region by Stephen Meek, another Hudson's Bay Company company trapper who was known for his "discovery" of Scott Valley, in regard to a crossing on the Klamath River near Hornbrook. Still others attribute the name to a local tribe of Native Americans.
The Siskiyou Trail stretched from California's Central Valley, through the Siskiyous, to Oregon's Willamette Valley. Originally based on existing Native American foot trails winding their way through river valleys, the Siskiyou Trail provided the shortest practical travel path between early settlements in California and Oregon in the 1820s.