# Tref Cybi West Isle of Anglesey. About 4,327 people (mid-2024 estimate) in 3.4 square kilometres. Tref Cybi had 4,360 usual residents at the census (ONS Census 2021). Ward. Code W05001503. In: [Wales](https://openindex.co.uk/wales) › [Isle of Anglesey](https://openindex.co.uk/isle-of-anglesey) ## Key figures - **Population: 4,360** (2021). Tref Cybi had 4,360 usual residents at the census (ONS Census 2021). Joint 2,204th least populated of 8,397. Source: Census 2021, England and Wales and Scotland's Census 2022 and Census 2021, Northern Ireland, 2021. Published 21 July 2026. https://openindex.co.uk/isle-of-anglesey/ward/tref-cybi#f-population - **People in radon Affected Area squares: 70%** (2022). About 70% of people in Tref Cybi live in a 1 km square that the radon atlas marks as a radon Affected Area. UK 44%. Source: Worked out by Open Index from the UKHSA and BGS radon atlas and census output areas. Published 1 December 2022. https://openindex.co.uk/isle-of-anglesey/ward/tref-cybi#f-radon-affected-share - **Gigabit broadband coverage: 96.0%** (January 2026). In Tref Cybi, 96.0% of homes and businesses could get gigabit-capable broadband in January 2026 (Ofcom). UK 87.8%. Source: Connected Nations (Ofcom), January 2026. Published 13 May 2026. https://openindex.co.uk/isle-of-anglesey/ward/tref-cybi#f-gigabit-coverage - **Claimant rate: 6.9%** (August 2026). In Tref Cybi, 6.9% of residents aged 16 to 64 were claiming out-of-work benefits in August 2026 (ONS via Nomis). UK 3.9%. Source: Claimant count (Nomis), August 2026. Published 15 September 2026. https://openindex.co.uk/isle-of-anglesey/ward/tref-cybi#f-claimant-rate ## On the map - [Radon Affected Area by ward](https://openindex.co.uk/map/radon-affected-areas?place=W05001503) (Worked out by Open Index · 2022): About 70% of people in Tref Cybi live in a 1 km square that the radon atlas marks as a radon Affected Area. - [Average house price by council](https://openindex.co.uk/map/house-prices?place=W05001503) (UK House Price Index · August 2026): Published for whole councils, so the map colours all of Isle of Anglesey. The outline is Tref Cybi. - [Crime and ASB by ward](https://openindex.co.uk/map/recorded-crime?place=W05001503) (Police recorded crime and outcomes (data.police.uk) · August 2026): Crime and anti-social behaviour for Tref Cybi. - [Population by ward](https://openindex.co.uk/map/population?place=W05001503) (Census 2021, England and Wales): Tref Cybi had 4,360 usual residents at the census. ## How Tref Cybi compares Each ward against every other ward the measure covers. | Measure | Tref Cybi | Rank | Compared with | | --- | --- | --- | --- | | Population | 4,360 | 6th least populated | 14 wards, Isle of Anglesey · 2021 | | People in radon Affected Area squares | 70% | joint 5th most people in radon Affected Areas | 14 wards, Isle of Anglesey · 2022 | | Gigabit broadband coverage | 96.0% | 2nd highest | 14 wards, Isle of Anglesey · Jan 2026 | | Claimant rate | 6.9% | highest | 14 wards, Isle of Anglesey · Aug 2026 | ## Is Tref Cybi safe? What police records show In the 12 months to August 2026, police recorded crimes and anti-social behaviour in Tref Cybi at a rate of 190.9 per 1,000 people. That compares with 73.9 per 1,000 people across Isle of Anglesey. Across Wales as a whole, the recorded crime rate was 96.7 per 1,000 people. In August 2026 alone, 85 cases of crime and anti-social behaviour were recorded in Tref Cybi. In the 12 months to August 2026, the most common types were violence and sexual offences (288), anti-social behaviour (176) and other crime (132). Worked out by Open Index from police.uk crime records and ONS and NISRA population estimates. Rates are per resident, so places that many people work in or visit, such as Westminster, the City of London and other city centres, have far higher rates than their residents alone would suggest. ## Figures for the whole of Isle of Anglesey These figures are published for the whole of Isle of Anglesey, not for each ward, so they describe all of Isle of Anglesey and not Tref Cybi alone. [See Isle of Anglesey](https://openindex.co.uk/isle-of-anglesey) - **Average house price: £236,308** (August 2026). Isle of Anglesey’s average house price was £236,308 in August 2026 (HM Land Registry). Down 0.4% in a year. Source: UK House Price Index, August 2026. Published 21 October 2026. - **Median full-time pay: £35,709** (2025). Full-time workers living in Isle of Anglesey earned a median of £35,709 in 2025 (ONS earnings survey). 85th lowest paid of 348. Source: Annual Survey of Hours and Earnings, 2025. Published 23 October 2025. - **House price to pay: 6.6×** (2025). A home in Isle of Anglesey costs 6.6 times local full-time pay. Joint 136th most affordable of 348. Source: Worked out by Open Index from the UK House Price Index and the ONS earnings survey. Published 21 October 2026. - **Population estimate: 68,607** (2025). Isle of Anglesey’s population was an estimated 68,607 in mid-2025 (ONS population estimates). Down 0.4% in a year. Source: Mid-year population estimates, 2025. Published 1 October 2026. ## Tref Cybi in brief Tref Cybi had 4,360 usual residents at the census. About 70% of people in Tref Cybi live in a 1 km square that the radon atlas marks as a radon Affected Area. In Tref Cybi, 96.0% of homes and businesses could get gigabit-capable broadband in January 2026. In Tref Cybi, 6.9% of residents aged 16 to 64 were claiming out-of-work benefits in August 2026. ## About - Type: Ward - Code: W05001503 - Constituency: [Ynys Môn †](https://openindex.co.uk/constituency/ynys-mon) - Council: [Isle of Anglesey](https://openindex.co.uk/isle-of-anglesey) - Nation: [Wales](https://openindex.co.uk/wales) - Area: 3.42 km² - People, mid-2024: 4,327* - Neighbourhoods: 3 - Output areas: 14 * People: worked out by Open Index from neighbourhood estimates, shared out by where people lived at the census (by area in Northern Ireland). This area's edges do not follow neighbourhood edges, so the figure is close but not exact. † Best fit: the constituency this ward mostly lies in. Its edges do not follow it. ## Next door [Ynys Gybi](https://openindex.co.uk/isle-of-anglesey/ward/ynys-gybi), [Parc a'r Mynydd](https://openindex.co.uk/isle-of-anglesey/ward/parc-ar-mynydd), [Bro'r Llynnoedd](https://openindex.co.uk/isle-of-anglesey/ward/bror-llynnoedd) ## Latest updates for Tref Cybi - August 2026 house prices published: HM Land Registry and partners · Oct 2026. - September 2026 rent published: ONS private rents · Oct 2026. - Dental practices updated: NHS England · Oct 2026. - Schools updated: Ofsted · Oct 2026. The same figures as JSON: https://openindex.co.uk/v1/places/W05001503 ## How to cite Source: Open Index, openindex.co.uk. Link to this page, https://openindex.co.uk/isle-of-anglesey/ward/tref-cybi, or to one figure with its anchor, https://openindex.co.uk/isle-of-anglesey/ward/tref-cybi#f-population. Open Index's own text and the figures it works out are licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Source data keeps its publishers' licences, named with each figure. Give each figure's period and source with it. Snapshot 2026.10.9. The HTML page: https://openindex.co.uk/isle-of-anglesey/ward/tref-cybi