Garden Grove club for detectorists, prospectors, and treasure hunters; the site says it was founded in 1982 and has passed 580 members. Direct fetches returned 403; meeting facts are indexed text of https://westcoastersclub.com/contact/ and the speaker page, which says the meeting runs 7:30 PM to 9:30 PM.
The map pin is the published meeting address. Meeting times change. Confirm with the club before you visit.