Gelligroes Mill is a water powered corn mill in Pontllanfraith, Caerphilly county borough, south Wales. It features an overshot wheel with a cast iron frame and wooden buckets. It was built around 1625, and much altered in its working life eventually falling into disuse in the late 1980s. It was soon restored and 1992. The mill was designated as a Grade II* listed building in 1962. It is believed to have been the last mill operating commercially in Monmouthshire. When fully operational the mill contained 2 pairs of rotating stones to grind barley and wheat.