Arfon (UK Parliament constituency)

Arfon
County constituency for the House of Commons
Boundary of Arfon in Wales for the 2010 general election.
Preserved county	Gwynedd
Electorate	41,138 (December 2010)
Major settlements	Bangor, Caernarfon
Current constituency
Created	2010
Member of parliament	Hywel Williams (Plaid Cymru)
Number of members	One
Created from	Caernarfon and Conwy
1885–1918
Replaced by	Caernarvonshire
Created from	Caernarvonshire
Overlaps
Welsh Assembly	Arfon, North Wales
European Parliament constituency	Wales

Arfon is a constituency of the House of Commons of the Parliament of the United Kingdom (at Westminster). Although the constituency is relatively large by geographical area, it is a predominantly urban rather than rural seat, with the majority of the population living in the two towns on which the constituency is based, Bangor and Caernarfon. "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, and replaced the old seat of Caernarfon. The same boundaries were used for the Arfon Welsh Assembly constituency in the 2007 Welsh Assembly election.

It is the smallest mainland constituency in the UK by electorate, and larger only than the two Scottish island constituencies, Na h-Eileanan an Iar and Orkney and Shetland.

The Arfon division of Caernarvonshire was a former UK Parliament constituency, which existed from 1885 until 1918. Before 1885 and after 1918 the area was part of the Caernarvonshire constituency. The Liberal MP William Rathbone represented the Arfon seat until 1895, followed by fellow Liberal William Jones. Upon the death of Mr Jones, Griffith C. Rees, for the Liberal Party, was elected unopposed at the subsequent by-election.