The view of Diamond Head rearing beyond the sands of Waikiki Beach makes one of Hawaii’s—and, indeed, America’s—truly legendary vistas. That stunning volcanic landform forms the centerpiece of Diamond Head State Monument, mere minutes from downtown Honolulu.
Diamond Head is a tuff cone. Formed as a volcanic explosion littered rocks and ash in a rim around the eruptive vent. Indeed, it’s one of the most famous examples of such a geologic feature, earning designation as a National Natural Landmark in 1968.
The Diamond Head tuff cone marks a roughly 300,000-year-old eruption of the Koolau Volcano forming the eastern shield of Oahu. It’s part of a series of relatively youthful features classified as the Honolulu Volcanic Series, much younger than the main eruptions that created Koolau. (Close to two million years ago, much of the Koolau Volcano slumped into the ocean. Erosion has sculpted the remnants of the shield volcano into the Koolau Range.)
The “diamond” in Diamond Head references the area’s glittery calcite crystals. To the Native Hawaiians, this grooved crest was Leahi, “Brow of the Ahi.” That reflects Diamond Head’s resemblance to the outline of a yellowfin tuna (ahi). Hawaiian tradition holds that Hiiaka, sister of the volcano goddess Pele, bestowed this name.
Looming 761 feet above Waikiki’s coastline, Diamond Head has long been a strategic landmark. Ancient Hawaiians lit fires on the summit to help sea canoes navigate. (They also built a temple to the god of wind—who, of course, had the power to snuff out those helpful flames—on top.) In 1904, the U.S. government bought the land around Diamond Head for the purposes of military fortification. Fort Ruger was established here shortly thereafter.
Bunkers, tunnels, and gateposts are among the remnants of the artillery battery installed at Diamond Head. Part of Oahu’s coastal defense system. Guns were not fired from the cone.
The trail to the summit also dates from that era. The headquarters of Diamond Head State Monument lies on the crater floor, and these facilities are ADA-accessible. The trail, however, is not. About an eighth of a mile long, it involves more than 550 feet of elevation gain and incorporates stairway sections.
Those who make the Diamond Head climb, though—properly outfitted with sun protection and water—enjoy stunning views from up top. The panorama includes Waikiki, Honolulu, and the eastward coastline running to Koko Head (another Honolulu Volcanic Series feature). The heights of the Koolau Range as well as the westerly Waianae Range are in view. And, if conditions are clear, you can gaze out to Maui, Molokai, and Lanai in the distance.
Expect plenty of company on the trail, and be respectful of folks nabbing selfies and other photos. You should allow about 1.5 to 2 hours to complete the hike. The monument opens daily at 6 AM; the last entry is 4 PM. That allows for the final visitors of the day to make the summit and back if they choose. The gates close at 6 PM, so plan ahead!
Diamond Head State Monument combines geologic drama, natural scenery, cultural heritage, and military history into one world-famous landscape. It’s definitely a must-visit for any Oahu vacationer!
-A pair of binoculars is a great accessory to bring along on a Diamond Head hike, especially during the winter.
-During the winter the summit often turns up views of spouting and splashing humpback whales offshore!