Argentia, NL, Unincorporated Place. Argentia is located on the west coast of the Avalon Peninsula of Newfoundland. Formerly the fishing community of Little Placentia (Petite Plaisance) founded by the French in the late 1600s, it was the site of English merchant premises after the Treaty of Utrecht (1713). A small silver-lead mine, opened near the community in the 1880s, operated sporadically until 1925; consequently Little Placentia was renamed Argentia (based on French or Latin words for silver) around 1900.

In 1940 the United States leased most of the small peninsula for a naval base. Argentia residents were resettled in nearby communities. The construction of the base created work for up to 15 000 Newfoundlanders and the base served the largest US task force in the Atlantic, 12 403 personnel in 1943. Near this base, in Placentia Bay, US President Roosevelt and British Prime Minister Churchill met aboard the USS Augusta to negotiate the historic Atlantic Charter in 1941. The base was gradually scaled down beginning in the mid 1950s, with the last facility being decommissioned in 1994. A small American undersea surveillance facility remains.

Argentia is now part of the town of Placentia and the site is managed by the Argentia Management Authority as an industrial park and deep-water port. A seasonal ferry terminal of Marine Atlantic is also located here. Argentia is Canada's foggiest place - with 206 days of fog per year - and one of the foggiest places in the world.