Piru (/ˈpaɪruː/ "Pie-roo") is a small unincorporated historic town and census-designated place located in eastern Ventura County, California, in the Santa Clara River Valley near the Santa Clara River and Highway 126, about seven miles (11 km) east of Fillmore and about 13 miles (21 km) west of Interstate 5. The population was 2,063 at the 2010 census, up from 1,196 when the 2000 census was enumerated.