Los Angeles County Science Fair http://www.lascifair.org/
Orange County Science & Engineering Fair http://www.ocsef.org/
Inland Science and Engineering Fair
http://www.rcoe.us/student-events/inland-science-engineering-fair/
Ventura County Science Fair http://www.vcoe.org/sc/ScienceFair.aspx
San Diego Festival of Science & Engineering https://www.lovestemsd.org/

California State Science Fair https://www.usc.edu/CSSF/