Castaic, California (2000 Census population 22,173 in the 91384 ZIP Coe) and area code 661 is an unincorporated community in Los Angeles County, USA. It lies north of Santa Clarita in Castaic Canyon, a few miles from the Santa Clarita Valley and Six Flags Magic Mountain amusement park. It is approximately 39 miles (63 km) from the downtown Los Angeles Civic Center.