Waterfall over Rock Run Grist mill dam at Susquehanna State Park, Havre De Grace, Maryland

Water tumbles down the front of the stone mill pond dam, splashing upon the rocks in the foreground. 

Rock Run Grist mill is located in Susquehanna State Park, Havre De Grace, Maryland. The mill was built around 1800 and was one of several owned by John Stump. The power source for the grist mill was the water in the mill pond behind this dam. Water flow to the mill was controlled by opening a gate on the left side of the pond. Water flowed from the gate down a man made stream, called a “mill race”, into a holding pond, called a “dip”. Water traveled out of the pond via an iron pipe, or “fore bay”, and into buckets on a multi-ton wheel attached to the mill house, causing the the wheel to turn. The wheel’s rotation drove a grindstone inside the mill.