Llanystumdwy is a village and community on the Ll?n Peninsula of Gwynedd in Wales, although it is not regarded as being part of Ll?n, but belonging instead to the local region of Eifionydd. It has a population of 1,949,Census 2001 and is located at the point where the A497 between Criccieth to the east, and Pwllheli to the west, crosses the Afon Dwyfor.