Caernarfon (UK Parliament constituency)

Caernarfon
Former County constituency for the House of Commons
Boundary of Caernarfon in Wales for the 2005 general election.
Preserved county	Gwynedd
Major settlements	Caernarfon
1950–2010
Number of members	One
Replaced by	Arfon and Dwyfor Meirionnydd
1536–1950
Number of members	One
Type of constituency	District of Boroughs constituency

Coordinates: 52°58′34″N 4°18′29″W / 52.976°N 4.308°W / 52.976; -4.308

Caernarfon was a parliamentary constituency centred on the town of Caernarfon in Wales. It elected one Member of Parliament (MP) by the first past the post system.

The constituency was created in 1536 as a District of Boroughs, represented in the House of Commons of England until 1707, in the House of Commons of Great Britain from 1707 to 1800, and in the House of Commons of the United Kingdom from 1801 to 1950. The District of Boroughs was abolished in 1950, and replaced with a county constituency of the same name, which was itself abolished in 2010.

Known as Carnarvon until 1832, and then as the Carnarvon Boroughs or Carnarvon District of Boroughs from 1832 to 1950 and as Caernarvon from 1950 to 1983, it is named after Caernarfon, the main town within the constituency. Its most famous member was David Lloyd George, who was MP for 55 years. When Lloyd George became prime minister in 1916 it became the first Welsh constituency to be represented by a serving prime minister. Plaid Cymru held the seat continuously from 1974 until its abolition in 2010, longer than they have held any other seat.