Mow Cop Castle is a folly at Mow Cop, near Harriseahead in the county of Staffordshire, England.
Traces of a prehistoric camp have been found here, but in 1754, Randle Wilbraham of nearby Rode Hall built an elaborate summerhouse looking like a medieval fortress and round tower.
The Castle was given to the National Trust in 1937. The same year over ten thousand Methodists met on the hill to commemorate the first Primitive Methodist Camp Meeting there.
The area around the castle was nationally famous for the quarrying of high-quality millstones ('querns') for use in water mills. Excavations at Mow Cop have found querns dating back to the Iron Age.
Though visitors were originally allowed inside the folly the area surrounding it has been fenced off due to an instance of suicide off the cliff edge.
On the turn of the millennium in the year 2000 a large fire was lit beside the folly as part of a network of communicating fires across the country.
Mow Cop and its folly are central images in Alan Garner's novel, Red Shift.