The Whistler Valley is located around the pass between the headwaters of the Green River and the upper-middle reaches of the Cheakamus. It is flanked by glaciated mountains on both sides; the Garibaldi Ranges on the side that contains the ski mountains, and a group of ranges with no collective name but which are part of the larger Pacific Ranges and are essentially fore-ranges of the Pemberton Icefield. Although there are a few other routes through the maze of mountains between the basin of the Lillooet River just east, the Cheakamus-Green divide is the lowest and most direct.