Castellfollit de la Roca () is a municipality in the comarca of Garrotxa, in the Province of Girona, Catalonia, Spain. The urban area is bordered by the confluence of the FluviÃÂ and Toronell rivers, between which the town's basalt cliff rises.
Castellfollit de la Roca is part of La Garrotxa Volcanic Zone Natural Park. The town is built on a basalt crag over 50 metres (160 feet) high and almost a kilometre long. It was formed by the overlaying of two lava flows.