The 16th Coast Artillery Regiment was a Coast Artillery regiment in the United States Army, manning the harbor defenses of Honolulu, Pearl Harbor and the perimeter of Oahu, Hawaii during World War II. The Regiment manned a large number of gun batteries at locations all over Oahu. The forts where they were assigned date to the 1890s, and had been in caretaker status for more than 30 years. On the morning of 7 December 1941, it was the soldiers of the 16th Coast Artillery who manned the anti-aircraft guns, bringing down six of the Japanese attack aircraft.