Irvine Underground is not the only group in the Orange County area.
Make sure to check out some of these great organizations too:
(Last updated January 2026)

Orange County

• 23b Shop
  https://www.23bshop.org/
  https://www.meetup.com/23bshop/
• OC 2600
  https://www.meetup.com/OC2600/
• OWASP OC
  https://www.meetup.com/owasp-oc/
• Cloud Security Alliance OC
  https://www.meetup.com/Cloud-Security-Alliance-CSA-Orange-County/

Greater Los Angeles Area

• LA 2600
  https://www.meetup.com/la2600/
• South Bay WASP
  https://www.meetup.com/southbaywasp/
• Null Space Labs
  https://www.meetup.com/nullspacelabs/
  https://032.la/
• OWASP LA
  https://www.meetup.com/OWASP-Los-Angeles/
• Hacker Drinkup
  https://hackerdrinkup.com/
• DC818
  https://dc818.org/

San Diego County

• DC 858/619
  https://www.dc858.org/
• OWASP SD
  https://www.meetup.com/Open-Web-Application-Security-Project-San-Diego-OWASP-SD/
• San Diego Underground
  https://www.sandiegounderground.org/

Inland Empire

• DC 909
  https://twitter.com/defcon909
• MAG Laboratory
  https://www.maglaboratory.org/