Sisquoc River

The Sisquoc River is a westward flowing river in northeastern Santa Barbara County, California. It is a tributary of the Santa Maria River, which is formed when the Sisquoc River meets the Cuyama River at the Santa Barbara County and San Luis Obispo County border just north of Garey. The river is 57.4 mile (92 km) long and originates on the north slopes of Big Pine Mountain, at approximately 6320 feet (1926 m). Big Pine Mountain is part of the San Rafael Mountains, which are part of the Transverse Ranges.

"Sisquoc" is a Chumash word meaning "quail". The river is shown on an 1846 diseño of the Rancho Cuyama grant as Arroyo de Siquico. Removal of dams on Sisquoc River tributaries expands the potential for restoration of steelhead. One tributary, Horse Creek (Horse Canyon), was dammed in 1968 and the 4.5 foot high, 60 foot wide dam eventually created a scour pool, increasing the drop to over 8 feet and creating an impassable barrier to spawning steelhead. The dam had completely silted in and no longer served to restrain sediment flows so was dynamited in 2006, and its sediment naturally eroded by 2011. A beaver dam created a large pool at the confluence of Horse Creek and the Sisquoc River and abundant steelhead trout were noted in a snorkel survey by fish biologist Matt Stoecker, including three fish 9 to 14 inches in size. The discovery of a male adult California Golden beaver (Castor canadensis subauratus) specimen collected as "wild caught" in 1906 "along the Sespe River in Ventura County" is physical evidence that Golden beaver were historically extant in coastal streams in southern California. The Sisquoc River used to receive steelhead running up from the Pacific Ocean via the Santa Maria River, but water removed by Twitchell Reservoir has interrupted the connection.

The Zaca Fire burned a large portion of the Sisqoc River watershed in the summer of 2007.