Piethorne Reservoir is the largest of several reservoirs in the Piethorne Valley above Milnrow, in the Metropolitan Borough of Rochdale, Greater Manchester, England. It was built in 1866.
During excavations at Piethorne in the mid-18th century, a Celtic spear-head with a 5-inch (130 mm) blade was unearthed, implying human habitation in the locality during the British Iron Age.
Walking in the South Pennines By Gladys Sellers, Jim Mansell
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