The Fort Ruger Historic District is a noncontiguous district which includes structures located in and on Diamond Head and on lands situated adjacent to the crater. This includes five batteries, seven fire control stations, two tunnels, and one building dating from 1909–1921. The district encompasses a portion of the remnants of Oahu’s earliest U.S. Army coastal defense fortification. The structures included in the district are significant as tangible reminders of the U.S. Army’s presence at Diamond Head crater. These structures are associated with the role of the coast artillery system on Oahu. Fort Ruger is significant in the history of the military in Hawaii as the first coastal defense fortification established by the U.S. Army in the islands.
This list of Hawaii’s historic properties is provided as a public service by Historic Hawaii Foundation. It is not the official list of properties designated on the Hawaii State Register of Historic Places. For official designations and determinations of eligibility, contact the State Historic Preservation Division of the Department of Land and Natural Resources of the State of Hawaii at 808-692-8015.