(Diamondhead) in Honolulu, Honolulu County, HI. 18th Av. SW 0.3 miles from jct with Kilauea Av., NW on Diamond Head Rd. 150’, SW on 18th Av. 0.3 miles to the tunnel. (N21 15.823 W157 48.051) Photo by Jack & June Schmidt 10-29-15.