Ynys Mon
Wales · County constituency · Isle of Anglesey borough
About the Ynys Mon constituency
Ynys Mon is a county constituency in Wales, covering most or all of Isle of Anglesey. The sitting MP is Llinos Medi (Plaid Cymru), first elected in July 2024.
At the 2024 general election, Plaid Cymru won Ynys Mon with 32.5% of the vote, ahead of the Conservatives on 30.5%, a majority of 637 votes. Turnout was 61.4%.
If a general election were held today, PollCheck's projection at the current seven-poll average has Plaid Cymru on 41.5% and the Conservatives on 22.7% in Ynys Mon, a margin of 18.8 points. The projection updates automatically as new polls are added.
Demographically, Ynys Mon is closely divided in the 2016 EU referendum (an estimated 50.9% voted Leave in 2016). About 32.3% of residents hold a degree, 68.2% of homes are owner-occupied, and the seat has around 31.5% of residents aged 65 or over (2021 Census).
Across the last 5 general elections on record, the seat has been won by Labour 3 times, the Conservatives 1 time, Plaid Cymru 1 time (earlier years may be on predecessor boundaries).
Who lives in Ynys Mon? Constituency demographics
From the 2021 Census and 2016 EU referendum estimates. Constituency-level data on 2024 boundaries.
How did Ynys Mon vote in 2024 and how would it vote now?
2024 vote shares from the HoC Library. Current projection is at the 7-poll average.
2024 general election
Current projection
Map of Ynys Mon
Switch between ward-level 2024 election winners and a demographic view. Ward winners are Britain Elects' / New Statesman modelled estimates with an average ~4pp margin of error per ward. The demographic view splits the seat into small neighbourhoods (around 1,500 residents each, from the 2021 Census). Hover any area for detail.
How Ynys Mon voted at the Senedd election (7 May 2026)
Ynys Mon sits entirely within the Senedd constituency of Bangor Conwy Môn. Senedd elections use a closed-list proportional system; each Senedd seat returns six members.
| Senedd constituency | Share of Ynys Mon | Winner | Runner-up | Seats (6 per constituency) |
|---|---|---|---|---|
| Bangor Conwy Môn | 100% | Plaid Cymru 44.9% | Reform UK 28.1% | 3 Plaid Cymru, 2 Reform UK, 1 Conservative |
Senedd 2026 results from official declarations. Overlap percentages are area-based using the post-2024 Westminster boundary against the new 16-seat Senedd boundary.
Ynys Mon within Isle of Anglesey
The Westminster constituency of Ynys Mon sits entirely within Isle of Anglesey Council. Local council elections are a separate ballot from Westminster general elections - English councils rotate their election cycles and Isle of Anglesey was not due to vote in 2026, so the figures below show the most recent council ward results available.
Council overlap
| Council | Share of seat |
|---|---|
| Isle of Anglesey | 100% |
Recent council by-elections
Council ward by-elections held inside this seat, most recent first. The result column shows which party won; the share column shows the top three parties’ vote shares on the day.
| Date | Ward | Result | Top 3 vote shares |
|---|---|---|---|
| 6 Feb 2026 | Ynys Gybi | Ref GAIN from PC | Ref 44% PC 25% Lab 12% |
| 28 Oct 2024 | Talybolion | Ind GAIN from PC | — |
| 21 Apr 2023 | Aethwy | PC HOLD | — |
Most recent council ward results
Latest council winner per ward. Where the council held a May 2026 election, those results are shown; otherwise we show the most recent available ward result (via DCLEAPIL, 2014-2024), or, where the seat was uncontested at the last election, the current sitting councillor from OpenCouncilData. The "Shift since GE2024" column is only computed for May 2026 results - earlier council votes pre-date the GE, so no directional shift is shown.
| Ward | GE2024 winner | Latest council winner | Shift since GE2024 | Turnout |
|---|
Projection trajectory
PollCheck's projection for Ynys Mon at each of the last 60 GB polls. Hover the chart for the underlying poll details.
Who has won Ynys Mon at past general elections?
2024 result is on current boundaries. The 2019 row is the UK Parliament's notional recalculation onto the 2024 boundaries (directly comparable to 2024). The 2010, 2015 and 2017 rows are on the boundaries in force at the time and aren't directly comparable.
| Year | Result | MP | Lab | Con | LD | Majority | Turnout |
|---|---|---|---|---|---|---|---|
| 2010 | Lab hold | Albert Owen | 33.4% | 22.5% | 7.5% | 2,461 | 68.8% |
| 2015 | Lab hold | Albert Owen | 31.1% | 21.2% | 2.2% | 229 | 69.9%+1.1 |
| 2017 | Lab hold | Albert Owen | 41.9% | 27.8% | 1.3% | 5,259 | 70.6%+0.7 |
| 2019notional | Conservative winner | Virginia Crosbie 2019 MP, pre-review boundary | 30.1% | 35.5% | 0.0% | 1,968 | 69.7%-0.9 |
| 2024 | PC gain from Con | Llinos Medi | 23.4% | 30.5% | 1.3% | 637 | 61.4%-8.3 |
Earlier years are on pre-2024 boundaries; comparable results on the new boundary will be added when sourced.
Constituencies most like Ynys Mon
Five seats with similar demographic profiles to Ynys Mon. Politics shown for context.
- ↑Age 65+31.5 / 32.1vs 22.7
- ↓Under 3523.3 / 22.6vs 30.2
- ↑Owner-occupied68.2 / 69.0vs 61.9
- ↑Age 65+31.5 / 30.5vs 22.7
- ↑Owner-occupied68.2 / 68.2vs 61.9
- ↓Under 3523.3 / 23.9vs 30.2
- ↑Age 65+31.5 / 30.6vs 22.7
- ↓Under 3523.3 / 23.6vs 30.2
- ↑Owner-occupied68.2 / 71.7vs 61.9
- ↑Age 65+31.5 / 30.4vs 22.7
- ↓Employed51.1 / 51.3vs 57.3
- ↓Under 3523.3 / 24.4vs 30.2
- ↑Age 65+31.5 / 31.4vs 22.7
- ↓Under 3523.3 / 25.7vs 30.2
- ↑Owner-occupied68.2 / 66.1vs 61.9
What would change this seat?
Move the sliders to set national vote shares. The per-seat projection updates live. Reset returns to the current 7-poll average.
Related
Sources
- 2024 general election results · UK Parliament Election Results portal and House of Commons Library briefing CBP-10009.
- Notional 2019 results on 2024 boundaries · UK Parliament Election Results portal. Recalculated by Parliament; carries assumptions about how 2019 voters would have distributed across the redrawn boundaries.
- Historic general election results (2010-2017) · House of Commons Library historic results files (on the boundaries in force at the time).
- Ward-level GE2024 estimates · Britain Elects / New Statesman - article by Ben Walker, underlying spreadsheet. Modelled from constituency totals; average ~4pp per-ward MoE.
- May 2026 council ward results · Democracy Club via PollCheck's locals 2026 dataset.
- Earlier council ward results (2014-2024) · DCLEAPIL v1.0 (Jason Leman, drawing on Andrew Teale's LEAP dataset and Democracy Club).
- Demographics · ONS Census 2021 (England and Wales), aggregated to constituency level using the ONS LSOA21 -> PCON24 best-fit lookup.
- EU referendum 2016 estimates · Constituency-level Leave vote estimates (Hanretty 2017 method).
- MP details and Cabinet roles · UK Parliament Members API. MP photos are fetched live from the same source.
- Boundary geometry and lookups · ONS Open Geography Portal (PCON24 boundaries, LSOA21 boundaries, LSOA21-WD24-LAD24 best-fit lookup).
- Current projection and trajectory · PollCheck's demographic swingometer applied to the rolling 7-poll average from aggregated GB polls. Not a true MRP - vote-share movements are applied through per-constituency sensitivity multipliers derived from demographic regressions.
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