# Treharris & Trelewis

South east Merthyr Tydfil. 8,625 people (mid-2024 estimate) in 9.9 square kilometres.

Treharris & Trelewis had 8,681 usual residents at the census (ONS Census 2021).

Middle area. Code W02000289. In: [Wales](https://openindex.co.uk/wales) › [Merthyr Tydfil](https://openindex.co.uk/merthyr-tydfil)

## Key figures

- **Median sale price: £147,500** (2025). The median price paid for a home in Treharris & Trelewis was £147,500 in 2025. Joint 482nd cheapest of 7,259. Source: Worked out by Open Index from HM Land Registry Price Paid Data. Published 28 September 2026. https://openindex.co.uk/merthyr-tydfil/treharris-and-trelewis#f-house-sales-median-price
- **Population: 8,681** (2021). Treharris & Trelewis had 8,681 usual residents at the census (ONS Census 2021). Joint 2,492nd most populated of 9,448. 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/merthyr-tydfil/treharris-and-trelewis#f-population
- **People in radon Affected Area squares: 80%** (2022). About 80% of people in Treharris & Trelewis 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/merthyr-tydfil/treharris-and-trelewis#f-radon-affected-share
- **Gigabit broadband coverage: 50.9%** (January 2026). In Treharris & Trelewis, 50.9% 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/merthyr-tydfil/treharris-and-trelewis#f-gigabit-coverage

## On the map

- [Radon Affected Area by middle area](https://openindex.co.uk/map/radon-affected-areas?place=W02000289) (Worked out by Open Index · 2022): About 80% of people in Treharris & Trelewis live in a 1 km square that the radon atlas marks as a radon Affected Area.
- [Sales per year by middle area](https://openindex.co.uk/map/house-sales-per-year?place=W02000289) (Worked out by Open Index · 2025): 104 homes were sold in Treharris & Trelewis in 2025.
- [Crime and ASB by middle area](https://openindex.co.uk/map/recorded-crime?place=W02000289) (Police recorded crime and outcomes (data.police.uk) · August 2026): Crime and anti-social behaviour for Treharris & Trelewis.
- [Population by middle area](https://openindex.co.uk/map/population?place=W02000289) (Census 2021, England and Wales): Treharris & Trelewis had 8,681 usual residents at the census.

## Recorded crime in Treharris & Trelewis

In the 12 months to August 2026, police recorded crimes and anti-social behaviour in Treharris & Trelewis at a rate of 56.5 per 1,000 people.
That compares with 110.6 per 1,000 people across Merthyr Tydfil.
Worked out by Open Index from police.uk crime records and ONS and NISRA population estimates.

| Kind of crime, 12 months to August 2026 | Count |
| --- | --- |
| Violence and sexual offences | 189 |
| Other crime | 105 |
| Anti-social behaviour | 82 |
| Criminal damage and arson | 49 |
| Vehicle crime | 38 |
| Burglary | 13 |
| Shoplifting | 8 |
| Drug offences | 2 |
| Robbery | 1 |
| Theft from the person | 0 |

Source: police.uk, 12 months to August 2026.

## How Treharris & Trelewis compares

Each middle area against every other middle area the measure covers.

| Measure | Treharris & Trelewis | Rank | Compared with |
| --- | --- | --- | --- |
| Median sale price | £147,500 | 4th most expensive | 7 middle areas, Merthyr Tydfil · 2025 |
| Population | 8,681 | 3rd most populated | 7 middle areas, Merthyr Tydfil · 2021 |
| People in radon Affected Area squares | 80% | 3rd most people in radon Affected Areas | 7 middle areas, Merthyr Tydfil · 2022 |
| Gigabit broadband coverage | 50.9% | lowest | 7 middle areas, Merthyr Tydfil · Jan 2026 |

## Is Treharris & Trelewis safe? What police records show

In the 12 months to August 2026, police recorded crimes and anti-social behaviour in Treharris & Trelewis at a rate of 56.5 per 1,000 people.
That compares with 110.6 per 1,000 people across Merthyr Tydfil.
Across Wales as a whole, the recorded crime rate was 96.7 per 1,000 people.
In August 2026 alone, 56 cases of crime and anti-social behaviour were recorded in Treharris & Trelewis.
In the 12 months to August 2026, the most common types were violence and sexual offences (189), other crime (105) and anti-social behaviour (82).
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 Merthyr Tydfil

These figures are published for the whole of Merthyr Tydfil, not for each middle area, so they describe all of Merthyr Tydfil and not Treharris & Trelewis alone. [See Merthyr Tydfil](https://openindex.co.uk/merthyr-tydfil)

- **Average house price: £148,656** (August 2026). Merthyr Tydfil’s average house price was £148,656 in August 2026 (HM Land Registry). Down 1.0% in a year. Source: UK House Price Index, August 2026. Published 21 October 2026.
- **Median full-time pay: £35,152** (2025). Full-time workers living in Merthyr Tydfil earned a median of £35,152 in 2025 (ONS earnings survey). 67th lowest paid of 348. Source: Annual Survey of Hours and Earnings, 2025. Published 23 October 2025.
- **House price to pay: 4.2×** (2025). A home in Merthyr Tydfil costs 4.2 times local full-time pay. Joint 15th 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: 58,362** (2025). Merthyr Tydfil’s population was an estimated 58,362 in mid-2025 (ONS population estimates). Down 0.6% in a year. Source: Mid-year population estimates, 2025. Published 1 October 2026.

## Treharris & Trelewis in brief

The median price paid for a home in Treharris & Trelewis was £147,500 in 2025.
Treharris & Trelewis had 8,681 usual residents at the census.
About 80% of people in Treharris & Trelewis live in a 1 km square that the radon atlas marks as a radon Affected Area.
In Treharris & Trelewis, 50.9% of homes and businesses could get gigabit-capable broadband in January 2026.

## About

- Type: Middle area
- Code: W02000289
- Ward: [Treharris †](https://openindex.co.uk/merthyr-tydfil/ward/treharris)
- Constituency: [Merthyr Tydfil and Aberdare †](https://openindex.co.uk/constituency/merthyr-tydfil-and-aberdare)
- Council: [Merthyr Tydfil](https://openindex.co.uk/merthyr-tydfil)
- Nation: [Wales](https://openindex.co.uk/wales)
- Area: 9.86 km²
- People, mid-2024: 8,625*
- Neighbourhoods: 5
- Output areas: 28

* People: worked out by Open Index by adding up the neighbourhood estimates inside this area.
† Best fit: the ward and constituency this middle area mostly lies in. Its edges do not follow theirs.

## Next door

[Merthyr Vale, Troed-y-rhiw & Bedlinog](https://openindex.co.uk/merthyr-tydfil/merthyr-vale-troed-y-rhiw-and-bedlinog), [Abercynon](https://openindex.co.uk/rhondda-cynon-taf/abercynon), [Ystrad Mynach & Nelson](https://openindex.co.uk/caerphilly/ystrad-mynach-and-nelson), [St Cattwg](https://openindex.co.uk/caerphilly/st-cattwg), [Mountain Ash](https://openindex.co.uk/rhondda-cynon-taf/mountain-ash)

## Latest updates for Treharris & Trelewis

- 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/W02000289

## How to cite

Source: Open Index, openindex.co.uk. Link to this page, https://openindex.co.uk/merthyr-tydfil/treharris-and-trelewis, or to one figure with its anchor, https://openindex.co.uk/merthyr-tydfil/treharris-and-trelewis#f-house-sales-median-price.

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/merthyr-tydfil/treharris-and-trelewis