Cobourg is a town in the Canadian province of Ontario, located in Southern Ontario  east of Toronto and east of Oshawa. It is the largest town in and seat of Northumberland County. Its nearest neighbour is Port Hope, to the west. It is located along Highway 401 (exits 472 and 474) and the former Highway 2 (now Northumberland County Road 2). To the south, Cobourg borders Lake Ontario. To the north, east and west, it is surrounded by Hamilton Township.