CSS Acadia is a former hydrographic surveying and oceanographic research ship once used by Canada to map its coastal waters. Launched in 1913 and named after the original name for Nova Scotia under French colonial rule, Acadia provided landmark surveys of Sable Island, the Bay of Fundy, and provided information instrumental in the establishment of the port of Churchill, Manitoba.
Later, the prefix CSS was changed to HMCS when Acadia spent two years from 1917 to 1919 on anti-submarine patrol in the Bay of Fundy and Gulf of St. Lawrence. During WWII, HMCS Acadia patrolled the waters at the entrance to Halifax Harbour, and also saw extensive action as a training ship. After the war, Acadia resumed work as a survey vessel for the third time, and in 1962 rescued hundreds of people from forest fires in Newfoundland. By the end of its career, CSS Acadia had charted nearly every metre of water in Atlantic Canada as well as a great percentage of the Eastern Arctic Coast.
Currently CSS Acadia belongs to the Maritime Museum of the Atlantic in Halifax where it is moored, and is open to the public every year from May to October. CSS Acadia is the only known ship still afloat to have survived the Halifax Explosion, and is also the only ship still afloat to have served the Royal Canadian Navy in both World Wars.