Fort Armstrong (Honolulu, Oahu, Hawaii)

Honolulu, Oahu · Hawaii

Quick BriefFort Armstrong was a Coast Artillery Fort built in 1907 and named after Brigadier General Samuel C. Armstrong. Built on fill over Ku-akau-kukui reef to protect Honolulu harbor, it served as a critical component of the Artillery District of Honolulu established on April 24, 1909. On December 13, 1951, President Truman transferred the land to the Territory of Hawaiʻi for harbor improvements.
Endicott SystemCoastal defense

History & Significance

In 1906 the Taft Board recommended a system of Coast Artillery batteries to protect Pearl Harbor and Honolulu. Fort Armstrong materialized from this defense initiative, positioned at the entrance to Honolulu Harbor.

It had one named Battery—Battery Tiernon—with two pedestal mounted 3-inch M1903 guns from 1911 to 1943, and was spread over 64 acres. The original garrison was the 1st Coast Artillery Company followed by the 104th Mine Co. operating the harbor mines.

The fort remained under Coast Artillery operations for over a decade and was formally designated a military reservation through executive orders in 1930. Army Corps of Engineers remained at the Fort until 1974, long after the island's transfer to territorial control.

The site later underwent significant physical transformation: a seawall was constructed 500 feet out from the original shoreline in 1948, the area was backfilled, the Army Corps of Engineers took over the post in 1949, and Kakaʻako Park was created over the landfill area. Today the former fort location comprises modern harbor facilities and recreational areas, with no original military structures remaining visible.

Key Facts

StateHawaii
LocationHonolulu, Oahu
Established1907
Decommissioned1950
War / eraOther / Unspecified
Current statusPrivate property

Sources

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