List of parliamentary constituencies in Gwynedd

Three constituencies cover the preserved county of Gwynedd for the House of Commons of the UK Parliament (Westminster), and are used also for elections to the Senedd. The current boundaries have been effective since the 2007 National Assembly for Wales election and the 2010 United Kingdom general election.^[1]^{[n 1]}.

The preserved county of Gwynedd shares its name with the southern bulk, the principal area, Gwynedd, Anglesey (Welsh: Ynys Môn), forms a second principal area, i.e. has its own local government council.

For Senedd elections, the constituencies each elect one assembly member and are grouped into additional-member electoral regions, in this instance the region is North Wales.

Westminster boundaries

From 2010

Constituency	Boundaries
1. Arfon CC (Westminster)	Parliamentary constituencies in Gwynedd 2010
2. Dwyfor Meirionnydd CC (Westminster)
3. Ynys Môn CC (Westminster)

Plaid Cymru ₪ Conservative † Labour ‡

Constituency	Electorate	Majority			Map reference above
Arfon	42,215	2,781	Hywel Williams ₪	Steffie Williams Roberts ‡	1
Dwyfor Meirionnydd	44,362	4,740	Liz Saville-Roberts ₪	Tomos Davies †	2
Ynys Môn	51,925	1,968	Virginia Crosbie †	Mary Roberts ‡	3

1997 to 2010

Constituency	Boundaries
1. Caernarfon CC (Westminster)	Parliamentary constituencies in Gwynedd pre-2010
2. Conwy CC (Westminster) (part)
3. Meirionnydd Nant Conwy CC (Westminster) (part)
4. Ynys Môn CC (Westminster)

Proposed boundary changes

The Boundary Commission for Wales submitted their final proposals in respect of the Sixth Periodic Review of Westminster Constituencies (the 2018 review) in September 2018. Although the proposals were immediately laid before Parliament they were not brought forward by the Government for approval. Accordingly, they did not come into effect for the 2019 election which took place on 12 December 2019, and which was contested using the constituency boundaries in place since 2010.

Under the terms of the Parliamentary Voting System and Constituencies Act 2011, the Sixth Review was based on reducing the total number of MPs from 650 to 600 and a strict electoral parity requirement that the electorate of all constituencies should be within a range of 5% either side of the electoral quota.

On 24 March 2020, the Minister of State for the Cabinet Office, Chloe Smith, issued a written statement to Parliament setting out the Government's thinking with regard to parliamentary boundaries. They propose to bring forward primary legislation to remove the statutory obligation to implement the 2018 Boundary Review recommendations, as well as set the framework for future boundary reviews in time for the next review which is due to begin in early 2021 and report no later than October 2023. It is proposed that the number of constituencies now remains at the current level of 650, rather than being reduced to 600, while retaining the requirement that the electorate should be no more than +/- 5% from the electoral quota.^[2]

Senedd boundaries

From 2007

Constituency	Senedd region	Constituency boundaries
1. Arfon CC (Senedd)	North Wales	Senedd constituencies in Gwynedd 2007
2. Dwyfor Meirionnydd CC (Senedd)	Mid and West Wales
3. Ynys Môn CC (Senedd)	North Wales

The North Wales region also includes seven Clwyd constituencies.The Mid and West Wales region also includes five Dyfed constituencies and two Powys constituencies.

1999 to 2007

Constituency	Assembly region	Constituency boundaries
1. Caernarfon CC (Assembly)	North Wales	Assembly constituencies in Gwynedd pre-2007
2. Conwy CC (Assembly) (part)	North Wales
3. Meirionnydd Nant Conwy CC (Assembly) (part)	Mid and West Wales
4. Ynys Môn CC (Assembly)	North Wales

Historical representation by party

Before 1974/1983 this table covers the historic counties of Anglesey, Carnarvonshire and Merionethshire. A cell marked → (with a different colour background to the preceding cell) indicates that the previous MP continued to sit under a new party name.

1832 to 1885

Conservative Liberal Peelite Whig

Constituency	1832	33	33	1835	36	1837	1841	46	1847	1852	1857
Anglesey	Williams-Bulkeley					Stanley			Williams-Bulkeley
Beaumaris	F. Paget								G. Paget		Stanley
Caernarvon	C. Paget	Nanney	C. Paget	L. Jones-Parry		Hughes		→
Caernarvonshire	Smith					Ormsby-Gore	E. Douglas-Pennant
Merionethshire	Vaughan				Richards					W. W. Wynne

1859 to 1885

Conservative Liberal

Constituency	1859	1865	66	1868	70	1874	1880	80	82
Anglesey	Williams-Bulkeley			Davies
Beaumaris	Stanley					Lloyd
Caernarvon	C. Wynne	Hughes							T. Jones-Parry
Caernarvonshire	E. Douglas-Pennant		G. Douglas-Pennant	T. Jones-Parry		G. Douglas-Pennant	C. Williams	Rathbone
Merionethshire	W. W. Wynne	W. R. Wynne		D. Williams	Holland

1885 to 1918

Conservative Liberal

Constituency	1885	1886	90	1895	99	00	06	Jan 10	15
Anglesey	R. Davies	Lewis		Ellis-Griffith
Arfon	Rathbone			W. Jones					Rees
Carnarvon	Jones-Parry	Swetenham	D. Lloyd George
Merionethshire	Robertson	Ellis			Edwards	Williams		Haydn Jones
Eifion	J. Roberts						E. Davies

1918 to 1950

Coalition Liberal (1918–22) / National Liberal (1922–23) Conservative Independent Labour Independent Liberals Labour Liberal

Constituency	1918	1922	23	1923	1929	1931	1935	45	1945
Anglesey	O. Thomas		R. Thomas		M. Lloyd George	→	→
Carnarvon	→			→		→	→	S. Davies	Price-White
Carnarvonshire	Breese	R. Jones		Owen		→	→		G. Roberts
Merionethshire	Haydn Jones								E. Roberts

1950 to 1983

Conservative Labour Liberal Plaid Cymru

Constituency	1950	1951	1966	1970	Feb 1974	1979
Anglesey	Lloyd George	Hughes				Best
Caernarfon	G. Roberts				Wigley
Merionethshire	E. Roberts	T. Jones	Edwards		Thomas
Conway¹	W. Jones	Thomas	Davies	W. Roberts

1983 to 2010

Conservative Labour Plaid Cymru

Constituency	1983	1987	1992	1997	2001
Ynys Môn	Best	Wyn Jones			Owen
Caernarfon	Wigley				H. Williams
Meirionnydd Nant Conwy	Thomas		Llwyd
Conway¹	W. Roberts			B. Williams

¹In 2003 the area of the former Aberconwy district, largely identical to the Conway constituency, was moved from the preserved county of Gwynedd to the preserved county of Clwyd. This constituency is graphed with the Gwynedd constituencies until the reorganisation of constituency boundaries in 2010.

2010 to present