Seaton Sluice harbour. Photo by Northumberland County Council, 1968.

Sir Ralph Delaval built the harbour at Seaton Sluice in the 17th century. It was large enough to take 14 ships, and was built to ship coal from the developing coal mines in the area. It was altered and enlarged in the mid 18th century when the `New Cut' was built. It became the centre for many industries including a glassworks, a brewery, brickworks and a quarry. It finally fell out of use in the mid 19th century. This is a Grade II listed building protected by law.