The area near Etchemin Lake was first described in 1828 as lovely by the surveyor Emmanuel. A few years later, in 1835, the region sees its first settler, Commissary General Sir Randolph Isham Routh KCB (1782–1858), who was given a land grant of 9,000 acres (36 km2) for his services to the Crown.
The new municipality of Lac-Etchemin was created in 2001 following the amalgamation of the city of Lac-Etchemin and the parish of Sainte-Germaine-du-Lac-Etchemin.