The Old Ausable Channel is a self-contained waterway in Lambton County, Ontario, Canada that runs through the Pinery Provincial Park and the community of Grand Bend. It is a 14 kilometre long river channel that was isolated from the Ausable River by the digging of canals for drainage in the late nineteenth century. Part of the Pinery Provincial Park's rare oak savanna, the channel is an important part of the region's ecosystem.