Diamond Head Summit

The summit of Diamond Head is 761 feet above sea level, at the top of the Fire Control Station, an Army observation post completed in 1911. From the top, Hawaii State Parks describes a view of Oʻahu's south shore from Koko Head to Waiʻanae, with Waikīkī below, and in winter, sometimes passing humpback whales. Bunkers built in 1915 line the crater rim nearby.

The Fire Control Station

The station was the reason the trail exists. Built at the summit between 1908 and 1910 and completed in 1911, it held instruments and plotting rooms used to aim artillery. Observers here triangulated targets and directed fire from Batteries Randolph and Dudley at Fort DeRussy in Waikīkī and Battery Harlow at Fort Ruger on the crater's outer slope.

It has four levels, reached by a spiral staircase and, originally, ladders. The outside was camouflaged with rubble set in concrete, and slits with metal shutters on each level faced the sea. The state's brochure calls it an engineering marvel of its time.

Climbing Through It

The trail enters the lowest level of the station at the top of a 99-step stairway. A lighted spiral staircase of 52 stairs climbs to the third level, where mounts for the observation equipment are still in place. You leave through the old seaward slits, then climb 54 metal stairs, added in the 1970s in place of a ladder, to the summit. Stair counts are from the 2012 park brochure.

The View

• West: Waikīkī and Honolulu along the shore toward Waiʻanae.
• East: the southeastern coast toward Koko Head, and on clear days the islands of Molokaʻi, Lānaʻi and Maui from the lookout on the rim.
• Below: the Diamond Head Lighthouse, built in 1917 on the coast outside the crater.
• Inside: the crater floor, 350 acres, wider than it is tall.

In winter, the agency notes, the view may include humpback whales passing offshore.

The Rim and the Way Down

From the summit, the brochure route continues along the rim and down 82 metal steps to a lower trail that loops back to the tunnel. Bunkers along the rim date from 1915. The area beyond them is closed and used as an emergency helicopter landing zone. Stay out of closed areas and bunkers.

Tips for the Top

• Follow the one-way loop the brochure maps; it exists to reduce congestion at the top.
• The old heiau here was dedicated to the god of wind, against strong updrafts. Keep a hand on your hat.
• Carry your water from the start.
• See the hike for time and difficulty, and the trail map for every stop.