Diamond Head Volcano State Landmark, Honolulu, Island of Oahu, Hawaii Also spelled Diamondhead (disambiguation) Location: From Waikiki follow Diamond Head Road nestled between Makapu'u Ave. and 18th Ave. Detailed directions at bottom of this article. GPS Coordinates for Geo Cachers: 21°15'35.0 N 157°48'42.3 W / 21.25972°N 157.81175°W / 21.25972; -157.81175 WHAT IS DIAMOND HEAD VOLCANO