Crag Lough is an inland lake at the southern edge of Northumberland National Park, 2.5 miles (4.0 km) north of Bardon Mill, and 0.5 miles (0.8 km) north of the B6318 Military Road road in Northumberland, northern England. At this point Hadrian's Wall is at the top of a line of crags with Crag Lough at the foot of the crags.