Largin Castle is situated approximately 4.5 kilometres (2.8 mi) west of Dobwalls, on a hill spur above the north-facing southern slope of the River Fowey valley, at an elevation of 130 meters (430 ft) above sea level. It is described in the Atlas of Hillforts of Britain and Ireland as having a complex shape occupying an area of 1.8 hectares (4.4 acres). The hillfort has an outer rampart and ditch enclosure with an entrance at its south. Within this, a smaller inner oval enclosure, also defined by ramparts and ditch, is offset to the north and occupies some 3/4ths of the interior. To the north and east of the hillfort, the valley drops away steeply to the Fowey and to a tributary stream, both at circa 50 meters (160 ft) elevation; to the south-west the land rises slowly to a local maximum of 193 meters (633 ft) at a distance of 690 meters (2,260 ft). A linear earthwork thought to be associated with the hillfort is found at the south-west, at the 190 meters (620 ft) contour, running for approximately 850 meters (2,790 ft) first due north, and then north-north-west.
- "Largin Castle – Iron Age Hillfort". The Cornish Bird. Elizabeth Dale. Retrieved 13 March 2019.
- Lock, G; Ralston, I (2017). "EN0626 Largin Castle, Cornwall". Atlas of Hillforts of Britain and Ireland [ONLINE]. Oxford University Department of Archaeology.
- "Magic Map". Department for Environment, Food and Rural Affairs. Retrieved 13 March 2019.
- "Aerial Photographs and archaeology" (PDF). Cornwall Council. Retrieved 13 March 2019.