The Bala Fault is a SW-NE trending geological fault in Wales that extends offshore into Cardigan Bay. In the offshore area it is a major normal fault and forms the bounding structure to the Cardigan Bay Basin, with a fill including about 2,500 metres (8,200 ft) of Lias Group. Onshore it is responsible for the lineament which runs through Bala and south of Cadair Idris to the coast at Tywyn. At its northeastern end it links to the similarly orientated .