Arfon is a constituency in Wales represented in the House of Commons of the UK Parliament at Westminster. Although it is relatively large by geographical area, the constituency is a predominantly urban rather than rural seat, with the majority of the population living in the two towns of Bethesda and Caernarfon, as well as in the city of Bangor, on which the constituency is based. "Arfon" is a historical name for the area, meaning "facing Anglesey"; it is also the name of the former district council. This seat was created by the Welsh Boundary Commission in time for the 2010 general election; it replaced the old seat of Caernarfon. Bangor was in the old seat of Conwy. The same boundaries were used for the Arfon Welsh Assembly constituency in the 2007 Welsh Assembly election.

Bethesda is a town and community in Gwynedd, Wales. It is on the banks of Afon Ogwen and on the edge of Snowdonia. It is 5 miles (8.0 km) from Bangor.