Located at 62 km northeast of the city of La Tuque, Grand Lake Bostonnais is encased between mountains. The surface of this lake which is frozen from November to April, has an average elevation of 413 meters above sea level. The north end of the lake is located at a distance of 4.4 kilometers south of the Quebec route 155 which links La Tuque and Chambord, Lac Saint-Jean. Grand Lake Bostonnais has a length of 10.8 km in the north-south direction. The southern part of the lake is 2.4 km wide and 2.8 km for northern part. A large island occupies the center of the southern part of the lake. A dozen other small islands are scattered mostly in the northern part of the lake. The lake is fed mostly on the east side by the discharge of the Lake Kiskissink; the latest is fed from the South by the discharge of Lescarbot Lake. Lake Kiskissink length is made parallel to the "Grand Lake Bostonnais". From the mouth of Lake Kiskissink, this segment of Bostonnais River has a length of 8.2 km. Between the two lakes is forestry center called Van Bruyssels. The mouth of the Grand Lake Bostonnais is located on the west side at the end of a little bay. Bostonnais River cross the lake. The rehabilitation of the dam Grand Lake Bostonnais is a joint project with Ducks Unlimited Canada, the Quebec Wildlife Foundation, Hydro-Québec and Zec Kiskissink for a total cost of $550,000. This project aims to maintain the lake level to promote breeding waterfowl in flooded areas and protection of spawning grounds in the outlet during the winter low flow period. The lake drains in the Bostonnais River.
Toponymy
The name of the lake commemorates Jean-Baptiste Bostonais, a trapper Abenaki originated in Boston, Massachusetts, in New England, who had a hunting territory in the region. His name often comes up in local place names with the Large and Small Bostonnais lakes, the Bostonnais channel, the Little Bostonnais River and Bostonnais island. The river gave its name to the village of La Bostonnais, which with La Tuque is the only community on the banks of this river. The toponym "Grand Lake Bostonnais" was officially registered on December 5, 1968, at the Bank of place names in Commission de toponymie du Québec
