Trapier's district was unmolested until February 25, 1865 when Union Admiral John Dahlgren's fleet sailed into Georgetown's harbor and captured the town. Trapier evacuated the town and its outlying fortifications previous to its occupation in concurrence with the surrender of Charleston. On March 1, 1865, Admiral Dahlgren's flagship, the USS Harvest Moon, struck a torpedo that had been placed there by Trapier's orders.