Chapais House was built in 1833 for the merchant Jean-Charles Chapais Sr. (1811–1885), one of the Fathers of Confederation. It later served as the residence of his son: the historian, journalist, and statesman Sir Thomas Chapais (1858–1946).

The slightly curved bellcast roof, large balconies surrounding the first floor, winding staircases leading to the terraces, and simply sculptured porticos make Chapais House a remarkable example of French-Canadian domestic architecture in the mid-19th century. This well-preserved residence also features exceptional interior detailing, including fine woodwork and joinery.

Jean-Charles Chapais Sr. played an active role in the economic and cultural development of the Kamouraska region. He represented Kamouraska as a Conservative member of the Legislative Assembly (1851–1867) and was the Commissioner of Public Works (1864–1867). As a delegate at the Quebec Conference and a Father of Confederation, he was appointed to the Senate in 1868, and held the position of Agriculture Minister and Receiver General in the Macdonald cabinets.

Sir Thomas Chapais was knighted in 1935 for his work as a Canadian historian. He is the author of many works, including his famous eight-volume Cours d’histoire du Canada. He was also a lawyer, a journalist, a member of the Quebec Legislative Assembly, and a Canadian senator.