Lockgate Mill also referred to locally and historically as Freethorpe Mill, 'Banham's Black Mill' and 'Duffel's Mill' is a windpump located on the Halvergate Marshes in the detached parish of Freethorpe within The Broads in the English county of Norfolk. It is approximately 2 miles (3.2 km) west of Great Yarmouth, and 3 miles (4.8 km) north-east of Berney Arms on the northern edge of Breydon Water.