Archipelago of Saint-Pierre Lake
The Archipelago of Lake Saint Pierre is a group of 103 islands in the western part of Lake Saint Pierre, in the Saint Lawrence River, Quebec, Canada. The islands form two main groups: the Berthier Islands to the north and the Sorel Islands to the south. About 22 coastal villages line the shores, and around 2,600 people lived on the islands in 2011.
Most islands are used for farming and ranching. Islands Dupas and Saint-Ignace-de-Loyola are more urbanized, while many others are rural. A network of small, often unpaved roads crosses the archipelago. Some islands are connected by bridges to the north side of the river—Saint-Ignace-de-Loyola, Dupas, and Castors. A ferry links Sorel (the south side) with Saint-Ignace Island, the largest island. Most other islands are only reachable by boat. Embarras Island is the smallest inhabited island on the south side.
Geologically, the archipelago sits in a delta formed after the last ice age. After the ice retreated, Champlain Sea covered the area about 12,000 years ago, leaving clay and marine sediments. The visible land today is made of more recent river sediments, rising up to about 7–8 meters above the river. Each spring floods deposit more silt, shaping the islands and sometimes making travel difficult, but the floods also help farming.
The Saint Lawrence River here widens and creates many channels between the islands. The landscape has low relief, typically 3–5 meters above the river. The area has a northern continental climate, cooler than Montreal but generally sunny. There is a long frost-free period that helps grow cereals, and winters are not extremely harsh.
The archipelago drains through 14 tributaries, covering a large area, and the region experiences a significant range of water flow. The south shore has fewer rivers but a larger combined flow on that side, while the north shore has more rivers with a smaller total flow.
The islands and Lake Saint Pierre are an important stopover for waterfowl migrating in eastern Canada. UNESCO recognized the ecological value of these wetlands in 2000.
People have lived here for a long time. The area was observed by Jacques Cartier in 1535 and by Samuel de Champlain in 1603. A wooden fort was built in 1642 to defend the area, was burned in 1647, and rebuilt in 1665. Settlers arrived in the following years, and grazing and farming became common. By 1710 the population was around 112, concentrated on the Beaver Islands, Dupas, Saint-Ignace, and Île Madame.
In the late 1920s, stones and dams were built to raise water levels in the shipping channel that runs south of the archipelago. Summer cottages grew along the Ravens Channel between the Crows and Lapierre Islands. The archipelago also figures in local culture, linked to the novels of Germaine Guèvremont, who lived on Îlette Pé for about 30 years; her house later became a museum related to the region.
The Archipelago of Lake Saint Pierre remains an area of natural beauty, farming life, and historic sites, with a rich connection to both nature and Canadian culture.
This page was last edited on 2 February 2026, at 22:41 (CET).