From its 4 headwater lakes (called Four Ponds - lakes are called "ponds" in Newfoundland and Labrador) in the Long Range Mountains on Newfoundland and Labrador's Great Northern Peninsula, the Main River drops quickly over boulder-strewn rapids. Flowing eastward, it levels out at the "Big Steady," a unique expanse of meadows, forest and wetlands - home for moose and caribou and the endangered marten. Below the Big Steady, the gradient steepens again as the Main races through a steep-walled 25-km canyon on its final dash to the sea, emptying into the Atlantic at the community of Sop's Arm. Its entire length is 57 km. The origin of the name is not known, but it first appeared on an Admiralty chart in 1897.
The Main River valley contains a unique old-growth forest, undisturbed by insect infestation, fire or blow-down for 7000 years. The spruce, tamarack and balsam fir here live up to 3 times their normal age and grow unusually large - resulting in a forest ecosystem unlike any other in North America. The Main is also one of the best Atlantic salmon rivers in the province. It is also arguably the most exciting river in Newfoundland for white-water paddling.
Although the old-growth forests of the Main are slated to be logged, much of the forest will be preserved so that this river's beauty and outstanding natural heritage will remain. In 2001 the Main River was designated as a Canadian Heritage River.