This vast region stretches along the southern (from Varennes to Bécancour) and northern (from Repentigny to Trois-Rivières) shores of the St. Lawrence River. It encompasses the drainage basins from the Lake Saint-Pierre tributaries, including the St. Lawrence River, as well as the Maskinongé, Yamachiche, Du-Loup, Aux-Sables, Richelieu, Yamaska, Saint-François and Nicolet rivers. The vineyards that wrap around Lake Saint-Pierre are planted on the site of the ancient Lampsilis Lake, a huge freshwater body dating back to 8,000 years B.C.
Geology and soils :
The soils in this region are mainly composed of marine sediments. Therefore, depending on the area, the soil may contain significant amounts of sand, clay or lime.
The relative humidity around the banks of the St. Lawrence River and Lake Saint-Pierre is more pronounced, and temperature variances aren’t quite as extreme. This region is generally colder than the area south of the Monteregian Hills, except for the areas of Varennes and Saint-Amable, which are among the warmest in Quebec. The north shore of the St. Lawrence River and Lake Saint-Pierre generally has a lot more snow cover than the south shore.