Muskrat Lake is located in the Whitewater Region of Renfrew County, Ontario, Canada. Said to be the home of the lake monster Mussie. Muskrat Lake drains into Muskrat River. Other than a few cottages and campgrounds, Cobden, is the only community on the lake's shore. Along its eastern shores is Sturgeon MountainLike many other lakes Muskrat Lake was formed about 10,000 years ago when the glaciers of the last ice age receded. At that point it was superseded by the much larger Champlain Sea.