# Ynys Môn (UK Parliament constituency)

Ynys Môn (Welsh pronunciation:; officially called Anglesey until 1983) is a constituency of the House of Commons of the Parliament of the United Kingdom. It elects one Member of Parliament (MP) by the first past the post system of election. It is one of five 'protected constituencies' within the UK, with boundaries defined by the Parliamentary Constituencies Act 2020 to be to those of Isle of Anglesey County Council where there must be a whole number of MPs rounded up to the nearest whole number with these boundaries.
The Ynys Môn Senedd constituency was created with the same boundaries in 1999 (as an Assembly constituency).
As of 2024, Ynys Môn is represented by Llinos Medi of Plaid Cymru.

## Constituency profile

The seat covers the isles of Anglesey and Holy Island. Incomes and house prices are slightly below average for the UK. Electoral Calculus describes the seat as "Traditionalist", characterised by socially conservative Labour-inclined voters with lower levels of income and formal education.

## History

The Laws in Wales Act 1535 (26 Hen. 8. c. 26) provided for a single county seat in the House of Commons for each of 12 historic Welsh counties (including Anglesey) and two for Monmouthshire. Using the modern year, starting on 1 January, these parliamentary constituencies were authorised in 1536.
The Act contains the following provision, which had the effect of enfranchising the shire of Anglesey:
   And that for this present Parliament, and all other Parliaments to be holden and kept for this Realm, one Knight shall be chosen and elected to the same Parliaments for every of the Shires of Brecknock, Radnor, Mountgomery and Denbigh, and for every other Shire within the said Country of Dominion of Wales;
The earliest known results are a fragment of the 1541 returns, in which the name of the Knight of the Shire for Anglesey (as Members of Parliament from county constituencies were known before the 19th century) has been lost. It is not known if Anglesey was represented in the parliaments of 1536 and 1539.
The borough constituency of Newborough, soon renamed Beaumaris, returned a member of parliament for the boroughs of Anglesey. It was abolished in 1885, leaving only the county constituency of Anglesey. The official name of the constituency in English was Anglesey, until it was replaced by the Welsh name Ynys Môn. Parliament approved the change, to take effect from the 1983 general election. This was purely an alteration of the official name, as no boundary changes were involved.

## Boundaries

Geographically, the constituency of Ynys Môn comprises the whole of the main island of Anglesey and the smaller Holy Island.
The Parliamentary Constituencies Act 2020 amends Schedule 2 to the Parliamentary Constituencies Act 1986 in granting Ynys Môn "protected" status, meaning the island must have a whole number of constituencies exclusively within the boundaries of the island.

## Members of Parliament
### MPs 1545–1640

| Parliament | Member |
| 1545 | William Bulkeley |
| 1547 | William Bulkeley |
| 1549 | Sir Richard Bulkeley (I) |
| 1553 (Mar) | Lewis Ab Owen ap Meurig |
| 1553 (Oct) | William Lewis |
| 1554 (Apr) | Sir Richard Bulkeley (I) |
| 1554 (Nov) | Sir Richard Bulkeley (I) |
| 1555 | William Lewis |
| 1558 | Rowland Ap Meredydd |
| 1562–3 | Richard Bulkeley (II) |
| 1571 | Sir Richard Bulkeley (I) |
| 1572 | Lewis Ab Owen ap Meurig |
| 1584 | Owen Holland |
| 1586 | Sir Henry Bagenal |
| 1588 | Richard Bulkeley (III) |
| 1593 | William Glynne |
| 1597 | Hugh Hughes |
| 1601 | Thomas Holland |
| 1604 | Sir Richard Bulkeley (II) |
| 1614 | Sir Richard Bulkeley (II) |
| 1621 | Richard Williams |
| 1624 | John Mostyn |
| 1625 | Sir Sackville Trevor |
| 1626 | Richard Bulkeley (IV) |
| 1628 | Richard Bulkeley (IV) |
| 1639–1640 | No Parliaments summoned |

### MPs after 1640

Short Parliament
* April 1640: John Bodvel
Long Parliament
* 1640–1644: John Bodvel (Royalist) – disabled to sit, 5 February 1644
* 1646–1648: Richard Wood – excluded in Pride's Purge, December 1648
Anglesey was unrepresented in Barebone's Parliament
First Protectorate Parliament
* 1654–1655: Col. George Twisleton
* 1654–1655: William Foxwist
Second Protectorate Parliament
* 1656–1658: Col. George Twisleton
* 1656–1658: Griffith Bodwrda
Third Protectorate Parliament
* 1659: Col. George Twisleton
| Election | Member | Party |
| April 1660 | The Viscount Bulkeley | Court |
| 1661 | Nicholas Bagenal | Court |
| February 1679 | Hon. Henry Bulkeley | Tory |
| August 1679 | Hon. Richard Bulkeley | Tory |
| 1685 | The Viscount Bulkeley | Tory |
| 1689 | Hon. Thomas Bulkeley | Tory |
| 1690 | The Viscount Bulkeley | Tory |
| 1704 | The Viscount Bulkeley | Tory |
| 1715 | Owen Meyrick | Whig |
| 1722 | The Viscount Bulkeley | Tory |
| 1725 | Hugh Williams | Whig |
| 1734 | Sir Nicholas Bayly, Bt | Opposition Whig |
| 1741 | John Owen | Opposition Whig |
| 1747 | Sir Nicholas Bayly, Bt | Opposition Whig |
| 1761 | Owen Meyrick | Whig |
| 1770 | Sir Nicholas Bayly, Bt | Opposition Whig |
| 1774 | The Viscount Bulkeley | Opposition, later allied to Burke and later still to Pitt |
| 1784 | Nicholas Bayly | Independent Whig, supported Pitt |
| 1790 | Hon. William Paget | Whig, supported Pitt |
| 1794 | Hon. Sir Arthur Paget | Whig |
| 1807 | Hon. Berkeley Paget | Whig |
| 1820 | The Earl of Uxbridge | Whig |
| 1832 | Sir Richard Williams-Bulkeley, Bt | Whig |
| 1837 | Hon. William Stanley | Whig |
| 1847 | Sir Richard Williams-Bulkeley, Bt | Whig |
| 1859 | Sir Richard Williams-Bulkeley, Bt | Liberal |
| 1868 | Richard Davies | Liberal |
| 1886 | Thomas Lewis | Liberal (Gladstonian) |
| 1895 | Ellis Ellis-Griffith | Liberal |
| 1918 | Sir Owen Thomas | Independent Labour |
| 1923 | Sir Robert Thomas, Bt | Liberal |
| 1929 | Lady Megan Lloyd George | Liberal |
| 1931 | Lady Megan Lloyd George | Independent Liberal |
| 1935 | Lady Megan Lloyd George | Liberal |
| 1951 | Cledwyn Hughes | Labour |
| 1979 | Keith Best | Conservative |
| 1983 | Name changed to Ynys Môn | Name changed to Ynys Môn |
| 1987 | Ieuan Wyn Jones | Plaid Cymru |
| 2001 | Albert Owen | Labour |
| 2019 | Virginia Crosbie | Conservative |
| 2024 | Llinos Medi | Plaid Cymru |

## Election results
### Elections in the 19th century
#### Elections in the 1830s

1830 general election: Anglesey :
| Party | Party | Candidate | Votes | % | ±% |
| | Whig | Henry Paget | Unopposed | Unopposed | Unopposed |
| Registered electors | Registered electors | Registered electors | c. 600 | | |
| | Whig hold | Whig hold | Whig hold | Whig hold | Whig hold |
1831 general election: Anglesey :
| Party | Party | Candidate | Votes | % | ±% |
| | Whig | Henry Paget | Unopposed | Unopposed | Unopposed |
| Registered electors | Registered electors | Registered electors | c. 600 | | |
| | Whig hold | Whig hold | Whig hold | Whig hold | Whig hold |
1832 general election: Anglesey :
| Party | Party | Candidate | Votes | % | ±% |
| | Whig | Richard Williams-Bulkeley | Unopposed | Unopposed | Unopposed |
| Registered electors | Registered electors | Registered electors | 1,187 | | |
| | Whig hold | Whig hold | Whig hold | Whig hold | Whig hold |
1835 general election: Anglesey :
| Party | Party | Candidate | Votes | % | ±% |
| | Whig | Richard Williams-Bulkeley | Unopposed | Unopposed | Unopposed |
| Registered electors | Registered electors | Registered electors | 1,155 | | |
| | Whig hold | Whig hold | Whig hold | Whig hold | Whig hold |
1837 Anglesey by-election :
| Party | Party | Candidate | Votes | % | ±% |
| | Whig | William Owen Stanley | 693 | 54.2 | N/A |
| | Conservative | Owen John Augustus Fuller Meyrick | 586 | 45.8 | N/A |
| Majority | Majority | Majority | 107 | 8.4 | N/A |
| Turnout | Turnout | Turnout | 1,279 | 88.2 | N/A |
| Registered electors | Registered electors | Registered electors | 1,450 | | |
| | Whig hold | Whig hold | Whig hold | Whig hold | Whig hold |
* Caused by Williams-Bulkeley's resignation
1837 general election: Anglesey :
| Party | Party | Candidate | Votes | % | ±% |
| | Whig | William Owen Stanley | Unopposed | Unopposed | Unopposed |
| Registered electors | Registered electors | Registered electors | 1,450 | | |
| | Whig hold | Whig hold | Whig hold | Whig hold | Whig hold |

#### Elections in the 1840s

1841 general election: Anglesey :
| Party | Party | Candidate | Votes | % | ±% |
| | Whig | William Owen Stanley | Unopposed | Unopposed | Unopposed |
| Registered electors | Registered electors | Registered electors | 2,434 | | |
| | Whig hold | Whig hold | Whig hold | Whig hold | Whig hold |
1847 general election: Anglesey :
| Party | Party | Candidate | Votes | % | ±% |
| | Whig | Richard Williams-Bulkeley | Unopposed | Unopposed | Unopposed |
| Registered electors | Registered electors | Registered electors | 2,465 | | |
| | Whig hold | Whig hold | Whig hold | Whig hold | Whig hold |

#### Elections in the 1850s

1852 general election: Anglesey :
| Party | Party | Candidate | Votes | % | ±% |
| | Whig | Richard Williams-Bulkeley | Unopposed | Unopposed | Unopposed |
| Registered electors | Registered electors | Registered electors | 2,577 | | |
| | Whig hold | Whig hold | Whig hold | Whig hold | Whig hold |
1857 general election: Anglesey :
| Party | Party | Candidate | Votes | % | ±% |
| | Whig | Richard Williams-Bulkeley | Unopposed | Unopposed | Unopposed |
| Registered electors | Registered electors | Registered electors | 2,310 | | |
| | Whig hold | Whig hold | Whig hold | Whig hold | Whig hold |
1859 general election: Anglesey :
| Party | Party | Candidate | Votes | % | ±% |
| | Liberal | Richard Williams-Bulkeley | Unopposed | Unopposed | Unopposed |
| Registered electors | Registered electors | Registered electors | 2,258 | | |
| | Liberal hold | Liberal hold | Liberal hold | Liberal hold | Liberal hold |

#### Elections in the 1860s

1865 general election: Anglesey :
| Party | Party | Candidate | Votes | % | ±% |
| | Liberal | Richard Williams-Bulkeley | Unopposed | Unopposed | Unopposed |
| Registered electors | Registered electors | Registered electors | 2,352 | | |
| | Liberal hold | Liberal hold | Liberal hold | Liberal hold | Liberal hold |
1868 general election: Anglesey :
| Party | Party | Candidate | Votes | % | ±% |
| | Liberal | Richard Davies | Unopposed | Unopposed | Unopposed |
| Registered electors | Registered electors | Registered electors | 3,496 | | |
| | Liberal hold | Liberal hold | Liberal hold | Liberal hold | Liberal hold |

#### Elections in the 1870s

1874 general election: Anglesey :
| Party | Party | Candidate | Votes | % | ±% |
| | Liberal | Richard Davies | 1,636 | 67.4 | N/A |
| | Conservative | Richard Williams-Bulkeley | 793 | 32.6 | N/A |
| Majority | Majority | Majority | 843 | 34.8 | N/A |
| Turnout | Turnout | Turnout | 2,429 | 76.6 | N/A |
| Registered electors | Registered electors | Registered electors | 3,173 | | |
| | Liberal hold | Liberal hold | Swing | N/A | |

#### Elections in the 1880s

1880 general election: Anglesey :
| Party | Party | Candidate | Votes | % | ±% |
| | Liberal | Richard Davies | 1,394 | 56.2 | ―11.2 |
| | Conservative | George Pritchard Rayner | 1,085 | 43.8 | +11.2 |
| Majority | Majority | Majority | 309 | 12.4 | ―22.4 |
| Turnout | Turnout | Turnout | 2,479 | 78.2 | +1.6 |
| Registered electors | Registered electors | Registered electors | 3,171 | | |
| | Liberal hold | Liberal hold | Swing | ―11.2 | |
1885 general election: Anglesey :
| Party | Party | Candidate | Votes | % | ±% |
| | Liberal | Richard Davies | 4,412 | 56.0 | ―0.2 |
| | Conservative | George Pritchard Rayner | 3,462 | 44.0 | +0.2 |
| Majority | Majority | Majority | 950 | 12.0 | ―0.4 |
| Turnout | Turnout | Turnout | 7,874 | 80.5 | +2.3 |
| Registered electors | Registered electors | Registered electors | 9,777 | | |
| | Liberal hold | Liberal hold | Swing | ―0.2 | |
1886 general election: Anglesey :
| Party | Party | Candidate | Votes | % | ±% |
| | Liberal | Thomas Lewis | 3,727 | 52.1 | ―3.9 |
| | Conservative | George Pritchard Rayner | 3,420 | 47.9 | +3.9 |
| Majority | Majority | Majority | 307 | 4.2 | ―7.8 |
| Turnout | Turnout | Turnout | 7,147 | 73.1 | ―7.4 |
| Registered electors | Registered electors | Registered electors | 9,777 | | |
| | Liberal hold | Liberal hold | Swing | ―3.9 | |

#### Elections in the 1890s

1892 general election: Anglesey :
| Party | Party | Candidate | Votes | % | ±% |
| | Liberal | Thomas Lewis | 4,420 | 62.1 | +10.0 |
| | Liberal Unionist | Morgan Lloyd | 2,702 | 37.9 | ―10.0 |
| Majority | Majority | Majority | 1,718 | 24.2 | +20.0 |
| Turnout | Turnout | Turnout | 7,122 | 70.6 | ―2.5 |
| Registered electors | Registered electors | Registered electors | 10,093 | | |
| | Liberal hold | Liberal hold | Swing | +10.0 | |
1895 general election: Anglesey :
| Party | Party | Candidate | Votes | % | ±% |
| | Liberal | Ellis Griffith | 4,224 | 56.9 | ―5.2 |
| | Conservative | J R Roberts | 3,197 | 43.1 | +5.2 |
| Majority | Majority | Majority | 1,027 | 13.8 | ―10.4 |
| Turnout | Turnout | Turnout | 7,421 | 74.3 | +3.7 |
| Registered electors | Registered electors | Registered electors | 9,993 | | |
| | Liberal hold | Liberal hold | Swing | ―5.2 | |

### Elections in the 20th century
#### Elections in the 1900s

1900 general election: Anglesey :
| Party | Party | Candidate | Votes | % | ±% |
| | Liberal | Ellis Griffith | Unopposed | Unopposed | Unopposed |
| Registered electors | Registered electors | Registered electors | | | |
| | Liberal hold | Liberal hold | Liberal hold | Liberal hold | Liberal hold |
1906 general election: Anglesey :
| Party | Party | Candidate | Votes | % | ±% |
| | Liberal | Ellis Griffith | 5,356 | 67.0 | N/A |
| | Conservative | C F Priestley | 2,638 | 33.0 | N/A |
| Majority | Majority | Majority | 2,718 | 34.0 | N/A |
| Turnout | Turnout | Turnout | 7,994 | 79.9 | N/A |
| Registered electors | Registered electors | Registered electors | 10,001 | | |
| | Liberal hold | Liberal hold | Swing | N/A | |
1907 Anglesey by-election :
| Party | Party | Candidate | Votes | % | ±% |
| | Liberal | Ellis Griffith | Unopposed | Unopposed | Unopposed |
| Registered electors | Registered electors | Registered electors | | | |
| | Liberal hold | Liberal hold | Liberal hold | Liberal hold | Liberal hold |

#### Elections in the 1910s

January 1910 general election: Anglesey :
| Party | Party | Candidate | Votes | % | ±% |
| | Liberal | Ellis Griffith | 5,888 | 70.7 | +3.7 |
| | Conservative | Richard Owen Roberts | 2,436 | 29.3 | ―3.7 |
| Majority | Majority | Majority | 3,452 | 41.4 | +7.4 |
| Turnout | Turnout | Turnout | 8,324 | 80.5 | +0.6 |
| Registered electors | Registered electors | Registered electors | 10,341 | | |
| | Liberal hold | Liberal hold | Swing | +3.7 | |
December 1910 general election: Anglesey :
| Party | Party | Candidate | Votes | % | ±% |
| | Liberal | Ellis Griffith | Unopposed | Unopposed | Unopposed |
| Registered electors | Registered electors | Registered electors | 10,341 | | |
| | Liberal hold | Liberal hold | Liberal hold | Liberal hold | Liberal hold |
1918 general election: Anglesey :
| Party | Party | Candidate | Votes | % | ±% |
| | Independent Labour | Owen Thomas | 9,038 | 50.4 | N/A |
| C | Liberal | Ellis Ellis-Griffith | 8,898 | 49.6 | N/A |
| Majority | Majority | Majority | 140 | 0.8 | N/A |
| Turnout | Turnout | Turnout | 17,936 | 69.4 | N/A |
| Registered electors | Registered electors | Registered electors | 25,836 | | |
| | Independent Labour gain from Liberal | Independent Labour gain from Liberal | Swing | | |
| C indicates candidate endorsed by the coalition government. ||||||

#### Elections in the 1920s

1922 general election: Anglesey :
| Party | Party | Candidate | Votes | % | ±% |
| | Independent Labour | Owen Thomas | 11,929 | 54.2 | +3.8 |
| | National Liberal | Robert Thomas | 10,067 | 45.8 | ―3.8 |
| Majority | Majority | Majority | 1,862 | 8.4 | +7.6 |
| Turnout | Turnout | Turnout | 21,996 | 80.5 | +11.1 |
| Registered electors | Registered electors | Registered electors | 27,320 | | |
| | Independent Labour hold | Independent Labour hold | Swing | +3.8 | |
1923 Anglesey by-election :
| Party | Party | Candidate | Votes | % | ±% |
| | Liberal | Robert Thomas | 11,116 | 53.3 | +7.5 |
| | Labour | Edward John | 6,368 | 30.5 | ―23.7 |
| | Unionist | Richard Owen Roberts | 3,385 | 16.2 | N/A |
| Majority | Majority | Majority | 4,748 | 22.8 | N/A |
| Turnout | Turnout | Turnout | 20,869 | 76.4 | ―4.1 |
| Registered electors | Registered electors | Registered electors | 27,320 | | |
| | Liberal gain from Independent Labour | Liberal gain from Independent Labour | Swing | +15.6 | |
1923 general election: Anglesey :
| Party | Party | Candidate | Votes | % | ±% |
| | Liberal | Robert Thomas | Unopposed | Unopposed | Unopposed |
| Registered electors | Registered electors | Registered electors | 28,135 | | |
| | Liberal hold | Liberal hold | Liberal hold | Liberal hold | Liberal hold |
1924 general election: Anglesey :
| Party | Party | Candidate | Votes | % | ±% |
| | Liberal | Robert Thomas | 13,407 | 63.9 | N/A |
| | Labour | Cyril O. Jones | 7,580 | 36.1 | N/A |
| Majority | Majority | Majority | 5,827 | 27.8 | N/A |
| Turnout | Turnout | Turnout | 20,987 | 74.0 | N/A |
| Registered electors | Registered electors | Registered electors | 28,343 | | |
| | Liberal hold | Liberal hold | Swing | N/A | |
1929 general election: Anglesey :
| Party | Party | Candidate | Votes | % | ±% |
| | Liberal | Megan Lloyd George | 13,181 | 49.4 | ―14.5 |
| | Labour | William Edwards | 7,563 | 28.4 | ―7.7 |
| | Unionist | Albert Hughes | 5,917 | 22.2 | N/A |
| Majority | Majority | Majority | 5,618 | 21.0 | ―6.8 |
| Turnout | Turnout | Turnout | 26,661 | 79.8 | +5.8 |
| Registered electors | Registered electors | Registered electors | 33,392 | | |
| | Liberal hold | Liberal hold | Swing | ―3.4 | |

#### Elections in the 1930s

1931 general election: Anglesey :
| Party | Party | Candidate | Votes | % | ±% |
| | Independent Liberal | Megan Lloyd George | 14,839 | 58.3 | +8.9 |
| | Conservative | Albert Hughes | 10,612 | 41.7 | +19.5 |
| Majority | Majority | Majority | 4,227 | 16.6 | ―4.4 |
| Turnout | Turnout | Turnout | 25,451 | 75.5 | ―4.3 |
| Registered electors | Registered electors | Registered electors | 33,700 | | |
| | Independent Liberals (UK, 1931) gain from Liberal | Independent Liberals (UK, 1931) gain from Liberal | | | |
1935 general election: Anglesey :
| Party | Party | Candidate | Votes | % | ±% |
| | Liberal | Megan Lloyd George | 11,227 | 44.5 | ―13.8 |
| | Conservative | Francis John Watkin Williams | 7,045 | 27.9 | ―13.8 |
| | Labour | Henry Jones | 6,959 | 27.6 | N/A |
| Majority | Majority | Majority | 4,182 | 16.6 | ±0.0 |
| Turnout | Turnout | Turnout | 25,231 | 74.4 | ―1.1 |
| Registered electors | Registered electors | Registered electors | 33,930 | | |
| | Liberal gain from Independent Liberals (UK, 1931) | Liberal gain from Independent Liberals (UK, 1931) | | | |

#### Elections in the 1940s

1945 general election: Anglesey :
| Party | Party | Candidate | Votes | % | ±% |
| | Liberal | Megan Lloyd George | 12,610 | 52.2 | +7.7 |
| | Labour | Cledwyn Hughes | 11,529 | 47.8 | +20.2 |
| Majority | Majority | Majority | 1,081 | 4.4 | ―12.2 |
| Turnout | Turnout | Turnout | 24,139 | 70.6 | ―3.8 |
| Registered electors | Registered electors | Registered electors | 34,210 | | |
| | Liberal hold | Liberal hold | Swing | | |

#### Elections in the 1950s

1950 general election: Anglesey :
| Party | Party | Candidate | Votes | % | ±% |
| | Liberal | Megan Lloyd George | 13,688 | 46.7 | ―5.5 |
| | Labour | Cledwyn Hughes | 11,759 | 40.0 | ―7.8 |
| | Conservative | J O Jones | 3,919 | 13.3 | N/A |
| Majority | Majority | Majority | 1,929 | 6.7 | +2.3 |
| Turnout | Turnout | Turnout | 29,366 | 82.7 | +12.1 |
| Registered electors | Registered electors | Registered electors | 35,490 | | |
| | Liberal hold | Liberal hold | Swing | +1.6 | |
1951 general election: Anglesey :
| Party | Party | Candidate | Votes | % | ±% |
| | Labour | Cledwyn Hughes | 11,814 | 40.1 | +0.1 |
| | Liberal | Megan Lloyd George | 11,219 | 38.2 | ―8.5 |
| | Conservative | O Meurig Roberts | 6,366 | 21.7 | +8.4 |
| Majority | Majority | Majority | 595 | 1.9 | N/A |
| Turnout | Turnout | Turnout | 29,399 | 81.4 | ―1.3 |
| Registered electors | Registered electors | Registered electors | 36,117 | | |
| | Labour gain from Liberal | Labour gain from Liberal | Swing | +4.3 | |
1955 general election: Anglesey :
| Party | Party | Candidate | Votes | % | ±% |
| | Labour | Cledwyn Hughes | 13,986 | 48.4 | +8.3 |
| | Liberal | John Williams Hughes | 9,413 | 32.6 | ―5.6 |
| | Conservative | Owen H. Hughes | 3,333 | 13.3 | ―8.4 |
| | Plaid Cymru | J Rowland Jones | 2,183 | 7.5 | N/A |
| Majority | Majority | Majority | 4,573 | 15.8 | +13.9 |
| Turnout | Turnout | Turnout | 28,915 | 80.4 | ―1.0 |
| Registered electors | Registered electors | Registered electors | 35,980 | | |
| | Labour hold | Labour hold | Swing | +6.9 | |
1959 general election: Anglesey :
| Party | Party | Candidate | Votes | % | ±% |
| | Labour | Cledwyn Hughes | 13,249 | 47.0 | ―1.4 |
| | Conservative | O Meurig Hughes | 7,005 | 24.9 | +11.6 |
| | Plaid Cymru | Robert Tudur Jones | 4,121 | 14.6 | +7.1 |
| | Liberal | Rhys Lloyd | 3,796 | 13.5 | ―19.1 |
| Majority | Majority | Majority | 6,244 | 22.1 | +6.3 |
| Turnout | Turnout | Turnout | 28,171 | 77.6 | ―2.8 |
| Registered electors | Registered electors | Registered electors | 36,281 | | |
| | Labour hold | Labour hold | Swing | –6.5 | |

#### Elections in the 1960s

1964 general election: Anglesey :
| Party | Party | Candidate | Votes | % | ±% |
| | Labour | Cledwyn Hughes | 13,553 | 48.1 | +1.1 |
| | Conservative | John Eilian Jones | 7,016 | 25.0 | +0.1 |
| | Liberal | E Gwyn Jones | 5,730 | 20.4 | +6.9 |
| | Plaid Cymru | R. Tudur Jones | 1,817 | 6.5 | ―8.1 |
| Majority | Majority | Majority | 6,537 | 23.1 | +1.0 |
| Turnout | Turnout | Turnout | 28,116 | 78.6 | +1.0 |
| Registered electors | Registered electors | Registered electors | 35,793 | | |
| | Labour hold | Labour hold | Swing | +0.5 | |
1966 general election: Anglesey :
| Party | Party | Candidate | Votes | % | ±% |
| | Labour | Cledwyn Hughes | 14,874 | 55.0 | +6.9 |
| | Conservative | John Eilian Jones | 9,576 | 35.4 | +10.4 |
| | Plaid Cymru | John Wynn Meredith | 2,596 | 9.6 | +3.1 |
| Majority | Majority | Majority | 5,298 | 19.6 | ―3.5 |
| Turnout | Turnout | Turnout | 27,046 | 73.2 | ―5.4 |
| Registered electors | Registered electors | Registered electors | 36,950 | | |
| | Labour hold | Labour hold | Swing | ―1.7 | |

#### Elections in the 1970s

1970 general election: Anglesey :
| Party | Party | Candidate | Votes | % | ±% |
| | Labour | Cledwyn Hughes | 13,966 | 43.2 | ―11.8 |
| | Conservative | John Eilian Jones | 9,220 | 28.5 | ―6.9 |
| | Plaid Cymru | John Lasarus Williams | 7,140 | 22.1 | +12.5 |
| | Liberal | Winston Roddick | 2,013 | 6.2 | N/A |
| Majority | Majority | Majority | 4,746 | 14.7 | ―4.9 |
| Turnout | Turnout | Turnout | 32,339 | 78.2 | +5.0 |
| Registered electors | Registered electors | Registered electors | 41,319 | | |
| | Labour hold | Labour hold | Swing | ―2.4 | |
February 1974 general election: Anglesey :
| Party | Party | Candidate | Votes | % | ±% |
| | Labour | Cledwyn Hughes | 14,652 | 41.8 | ―1.4 |
| | Conservative | Thomas Vivan Lewis | 8,898 | 25.4 | ―3.1 |
| | Plaid Cymru | Dafydd Iwan | 7,610 | 21.7 | ―0.4 |
| | Liberal | Edwin Jones | 3,882 | 11.1 | +4.9 |
| Majority | Majority | Majority | 5,754 | 16.4 | +1.7 |
| Turnout | Turnout | Turnout | 35,042 | 80.2 | +2.0 |
| Registered electors | Registered electors | Registered electors | 43,685 | | |
| | Labour hold | Labour hold | Swing | +0.8 | |
October 1974 general election: Anglesey :
| Party | Party | Candidate | Votes | % | ±% |
| | Labour | Cledwyn Hughes | 13,947 | 41.6 | ―0.2 |
| | Conservative | Vivan Lewis | 7,975 | 23.8 | ―1.6 |
| | Plaid Cymru | Dafydd Iwan | 6,410 | 19.1 | ―2.6 |
| | Liberal | Mervyn Ankers | 5,182 | 15.5 | +4.4 |
| Majority | Majority | Majority | 5,972 | 17.8 | +1.4 |
| Turnout | Turnout | Turnout | 33,514 | 76.1 | ―4.1 |
| Registered electors | Registered electors | Registered electors | 44,026 | | |
| | Labour hold | Labour hold | Swing | +0.7 | |
1979 general election: Anglesey :
| Party | Party | Candidate | Votes | % | ±% |
| | Conservative | Keith Best | 15,100 | 39.0 | +15.2 |
| | Labour | Elystan Morgan | 12,283 | 31.7 | ―9.9 |
| | Plaid Cymru | John Lasarus Williams | 7,863 | 20.3 | +1.2 |
| | Liberal | John Gwynedd Jones | 3,500 | 9.0 | ―6.5 |
| Majority | Majority | Majority | 2,817 | 7.3 | N/A |
| Turnout | Turnout | Turnout | 38,746 | 81.2 | +5.1 |
| Registered electors | Registered electors | Registered electors | 47,726 | | |
| | Conservative gain from Labour | Conservative gain from Labour | Swing | +12.5 | |

#### Elections in the 1980s

1983 general election: Ynys Môn :
| Party | Party | Candidate | Votes | % | ±% |
| | Conservative | Keith Best | 15,017 | 37.5 | ―1.5 |
| | Plaid Cymru | Ieuan Wyn Jones | 13,333 | 33.3 | +13.0 |
| | Labour | Tudor Williams | 6,791 | 16.9 | ―14.8 |
| | SDP | David Thomas | 4,947 | 12.3 | +3.3 |
| Majority | Majority | Majority | 1,684 | 4.2 | ―3.1 |
| Turnout | Turnout | Turnout | 40,088 | 79.6 | ―1.6 |
| Registered electors | Registered electors | Registered electors | 50,359 | | |
| | Conservative hold | Conservative hold | Swing | | |
1987 general election: Ynys Môn :
| Party | Party | Candidate | Votes | % | ±% |
| | Plaid Cymru | Ieuan Wyn Jones | 18,580 | 43.2 | +9.9 |
| | Conservative | Roger Evans | 14,282 | 33.2 | ―4.3 |
| | Labour | Colin Parry | 7,252 | 16.9 | ±0.0 |
| | SDP | Ieuan Wilson Evans | 2,863 | 6.7 | ―5.6 |
| Majority | Majority | Majority | 4,298 | 10.0 | N/A |
| Turnout | Turnout | Turnout | 42,977 | 81.7 | +2.1 |
| Registered electors | Registered electors | Registered electors | 52,633 | | |
| | Plaid Cymru gain from Conservative | Plaid Cymru gain from Conservative | Swing | +7.2 | |

#### Elections in the 1990s

1992 general election: Ynys Môn :
| Party | Party | Candidate | Votes | % | ±% |
| | Plaid Cymru | Ieuan Wyn Jones | 15,984 | 37.1 | ―6.1 |
| | Conservative | Gwynn Rowlands | 14,878 | 34.6 | +1.4 |
| | Labour | Robin Jones | 10,126 | 23.5 | +6.6 |
| | Liberal Democrats | Pauline Badger | 1,891 | 4.4 | ―2.3 |
| | Natural Law | Susan Parry | 182 | 0.4 | N/A |
| Majority | Majority | Majority | 1,106 | 2.5 | ―7.5 |
| Turnout | Turnout | Turnout | 43,061 | 80.6 | ―1.1 |
| Registered electors | Registered electors | Registered electors | 53,412 | | |
| | Plaid Cymru hold | Plaid Cymru hold | Swing | ―3.7 | |
1997 general election: Ynys Môn :
| Party | Party | Candidate | Votes | % | ±% |
| | Plaid Cymru | Ieuan Wyn Jones | 15,756 | 39.5 | +2.4 |
| | Labour | Owen Edwards | 13,275 | 33.2 | +9.7 |
| | Conservative | Gwilym Owen | 8,569 | 21.5 | ―13.1 |
| | Liberal Democrats | Deric Burnham | 1,537 | 3.8 | ―0.6 |
| | Referendum | Hugh Gray-Morris | 793 | 2.0 | N/A |
| Majority | Majority | Majority | 2,481 | 6.3 | +3.8 |
| Turnout | Turnout | Turnout | 39,930 | 75.4 | ―5.2 |
| Registered electors | Registered electors | Registered electors | 53,294 | | |
| | Plaid Cymru hold | Plaid Cymru hold | Swing | +3.7 | |

### Elections in the 21st century
#### Elections in the 2000s

2001 general election: Ynys Môn :
| Party | Party | Candidate | Votes | % | ±% |
| | Labour | Albert Owen | 11,906 | 35.0 | +1.8 |
| | Plaid Cymru | Eilian Williams | 11,106 | 32.6 | ―6.9 |
| | Conservative | Albie Fox | 7,653 | 22.5 | +1.0 |
| | Liberal Democrats | Nicholas Bennett | 2,772 | 8.1 | +4.3 |
| | UKIP | Francis Wykes | 359 | 1.1 | N/A |
| | Independent | Nona Donald | 222 | 0.7 | N/A |
| Majority | Majority | Majority | 800 | 2.4 | N/A |
| Turnout | Turnout | Turnout | 34,018 | 63.7 | ―11.7 |
| Registered electors | Registered electors | Registered electors | 53,398 | | |
| | Labour gain from Plaid Cymru | Labour gain from Plaid Cymru | Swing | +4.3 | |
2005 general election: Ynys Môn :
| Party | Party | Candidate | Votes | % | ±% |
| | Labour | Albert Owen | 12,278 | 34.6 | ―0.4 |
| | Plaid Cymru | Eurig Wyn | 11,036 | 31.1 | ―1.5 |
| | Independent | Peter Rogers | 5,216 | 14.7 | N/A |
| | Conservative | James Roach | 3,915 | 11.0 | ―11.5 |
| | Liberal Democrats | Sarah Green | 2,418 | 6.8 | ―1.3 |
| | UKIP | Elaine Gill | 367 | 1.0 | ―0.1 |
| | Legalise Cannabis | Tim Evans | 232 | 0.7 | N/A |
| Majority | Majority | Majority | 1,242 | 3.5 | +1.1 |
| Turnout | Turnout | Turnout | 35,462 | 67.5 | +3.8 |
| Registered electors | Registered electors | Registered electors | 52,512 | | |
| | Labour hold | Labour hold | Swing | +0.6 | |

#### Elections in the 2010s

2010 general election: Ynys Môn :
| Party | Party | Candidate | Votes | % | ±% |
| | Labour | Albert Owen | 11,490 | 33.4 | ―1.2 |
| | Plaid Cymru | Dylan Rees | 9,029 | 26.2 | ―4.9 |
| | Conservative | Anthony Ridge-Newman | 7,744 | 22.5 | +11.5 |
| | Liberal Democrats | Matt Wood | 2,592 | 7.5 | +0.7 |
| | Independent | Peter Rogers | 2,225 | 6.5 | ―8.2 |
| | UKIP | Elaine Gill | 1,201 | 3.5 | +2.5 |
| | Christian | David Owen | 163 | 0.5 | N/A |
| Majority | Majority | Majority | 2,461 | 7.2 | +3.7 |
| Turnout | Turnout | Turnout | 34,444 | 68.8 | +1.3 |
| Registered electors | Registered electors | Registered electors | 50,075 | | |
| | Labour hold | Labour hold | Swing | +1.8 | |
2015 general election: Ynys Môn :
| Party | Party | Candidate | Votes | % | ±% |
| | Labour | Albert Owen | 10,871 | 31.1 | ―2.3 |
| | Plaid Cymru | John Rowlands | 10,642 | 30.5 | +4.3 |
| | Conservative | Michelle Willis | 7,393 | 21.2 | ―1.3 |
| | UKIP | Nathan Gill | 5,121 | 14.7 | +11.2 |
| | Liberal Democrats | Mark Rosenthal | 751 | 2.2 | ―5.3 |
| | Socialist Labour | Liz Screen | 148 | 0.4 | N/A |
| Rejected ballots | Rejected ballots | Rejected ballots | 67 | | |
| Majority | Majority | Majority | 229 | 0.6 | ―6.6 |
| Turnout | Turnout | Turnout | 34,926 | 69.9 | +1.1 |
| Registered electors | Registered electors | Registered electors | 49,939 | | |
| | Labour hold | Labour hold | Swing | ―3.2 | |
Of the 67 rejected ballots:
* 51 were either unmarked or it was uncertain who the vote was for.
* 16 voted for more than one candidate.
2017 general election: Ynys Môn :
| Party | Party | Candidate | Votes | % | ±% |
| | Labour | Albert Owen | 15,643 | 41.9 | +10.8 |
| | Conservative | Tomos Davies | 10,384 | 27.8 | +6.6 |
| | Plaid Cymru | Ieuan Wyn Jones | 10,237 | 27.4 | ―3.1 |
| | UKIP | James Turner | 624 | 1.7 | ―13.0 |
| | Liberal Democrats | Sarah Jackson | 479 | 1.3 | ―0.9 |
| Majority | Majority | Majority | 5,259 | 14.1 | +13.5 |
| Turnout | Turnout | Turnout | 37,367 | 70.6 | +0.7 |
| Registered electors | Registered electors | Registered electors | 52,921 | | |
| | Labour hold | Labour hold | Swing | +2.1 | |
2019 general election: Ynys Môn :
| Party | Party | Candidate | Votes | % | ±% |
| | Conservative | Virginia Crosbie | 12,959 | 35.5 | +7.7 |
| | Labour | Mary Roberts | 10,991 | 30.1 | ―11.8 |
| | Plaid Cymru | Aled ap Dafydd | 10,418 | 28.5 | +1.1 |
| | Brexit Party | Helen Jenner | 2,184 | 6.0 | N/A |
| Rejected ballots | Rejected ballots | Rejected ballots | 121 | | |
| Majority | Majority | Majority | 1,968 | 5.4 | N/A |
| Turnout | Turnout | Turnout | 36,552 | 70.4 | ―0.2 |
| Registered electors | Registered electors | Registered electors | 51,925 | | |
| | Conservative gain from Labour | Conservative gain from Labour | Swing | +9.8 | |
Of the 121 rejected ballots:
* 96 were either unmarked or it was uncertain who the vote was for.
* 24 voted for more than one candidate.
* 1 had want of official mark.

#### Elections in the 2020s

2024 general election: Ynys Môn :
| Party | Party | Candidate | Votes | % | ±% |
| | Plaid Cymru | Llinos Medi | 10,590 | 32.5 | +4.0 |
| | Conservative | Virginia Crosbie | 9,953 | 30.5 | −5.0 |
| | Labour | Ieuan Môn Williams | 7,619 | 23.4 | −6.7 |
| | Reform UK | Emmett Jenner | 3,223 | 9.9 | +3.9 |
| | Green | Martin Schwaller | 604 | 1.9 | N/A |
| | Liberal Democrats | Leena Farhat | 439 | 1.4 | N/A |
| | Monster Raving Loony | Sir Grumpus L Shorticus | 156 | 0.5 | N/A |
| | Libertarian | Sam Andrew Wood | 44 | 0.1 | N/A |
| Majority | Majority | Majority | 637 | 2.0 | N/A |
| Turnout | Turnout | Turnout | 32,628 | 61.4 | −8.3 |
| Registered electors | Registered electors | Registered electors | 53,141 | | |
| | Plaid Cymru gain from Conservative | Plaid Cymru gain from Conservative | Swing | +4.5 | |