Around 1820, a small cluster of homes was built on the present site of the municipality, named Waterloo Settlement by the English immigrants after the Anglo-Prussian victory at Waterloo. In 1845, the Municipality of St-Dunstan was formed, named after the local parish of Saint-Dunstan-du-Lac-Beauport. It was abolished in 1847, but reestablished as the Parish Municipality of Saint-Dunstan-du-Lac-Beauport in 1855. In common use, it was only known as Lac-Beauport, prompting the town council to officially change the name in 1989.