The Cowichan Lake area is in the heart of the Insular Mountains, Vancouver Island's main mountain range. The average height of most mountains is between 900 and 1200 meters.

Cowichan Lake, the 2nd largest lake on Vancouver Island (26 miles/42 km long), is the headwaters of the Cowichan River. The lake flows through a weir, then becomes the river which supplies all the water needs for the residential area around Duncan and the Crofton Pulp Mill. The river is world famous for its trout, steelhead, and salmon fishing. It is a very important spawning river for salmon and is now protected as a Heritage River.

The major commercial trees are Douglas fir, hemlock, and cedar although there are other significant stands of alder and maple within the "Coastal Douglas-fir" zone. Arbutus trees are also found in some drier regions. Salal, ferns, mosses, and a variety of berry bushes cover the forest floor as do many edible mushrooms.

The west end of the region within the "Coastal western hemlock - pacific silver fir" zone is dominated with high quality stands of western red cedar, yellow cedar, hemlock, and silver fir. The forest floor in this region is similar to the above, but you also find sphagnum bogs in wetter areas.