High Quality Content by WIKIPEDIA articles! Cobourg (pop. 18,500) is a town in the Canadian province of Ontario, located in Southern Ontario 95 km east of Toronto. It is the largest town in Northumberland County. Its nearest neighbour is Port Hope, 7 km (4 mi) 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, while to the north, east and west, it is surrounded by Hamilton Township.