A miniature castle with crenellated battlements, corner towers, balistraria (arrow slits), and a courtyard, this coral-stone building was moved block by block to the Iolani Palace grounds in 1965 in order to make room for the Hawaii State Capitol (OA46). Unfortunately, the walls were rebuilt upside down, with the larger bottom blocks now resting on the top. The plaster finish, scored to emulate Gothic stone, replicates the original finish and rectifies the reconstruction error. Some of the coral block used in the barracks came from the demolition of the government printing office, but most of it was newly quarried by prisoners. This building was one of the last in Hawaii to utilize coral block, as its builder, J. G. Osborne, introduced the kingdom to reinforced-concrete-block construction at this time.
The castlelike design reflected the building's original purpose as the headquarters and barracks of the Royal Household Guards. It served this function until the overthrow of the monarchy. In the ensuing years, the building was used for a variety of purposes, mostly military, and included occupancy by the U.S. Army Quartermaster Corps and the Hawaii National Guard.
Theodore C. Heuck was the first professional architect known to reside in the Islands. Arriving in 1850 from Hamburg, Germany, at the age of twenty, he remained in Hawaii until 1874. During that time, this carpenter and architect also operated a merchandising business and was active in politics, serving in the Hawaiian legislature and as consul for Denmark, Hanover, and the North German Republic. In addition to this structure, he designed the Royal Mausoleum (OA77) and the original Queen's Hospital (1870; demolished).