Photo: Martin Ridley · Public domainMore households in terraced houses than 99% of UK towns: 73%
Across Wales’s towns, 43% of adults are married or in a civil partnership; in Treherbert, 38%. More residents who describe themselves as White British than in 95% of UK towns: 97%. This Mid Glamorgan town is home to 5,427 residents in 2,494 households, by the 2021 Census. Households in detached houses account for 4.6%.
What the Census says about Treherbert’s people
More with no religion than most
65% of residents answered “no religion” in 2021 and 28% Christian, against 47% and 43% across Wales’s towns. Ethnicity & religion ↓
Written from the data on this page: ONS Census 2021 (output areas summed to the 2022 built-up area) and ONS mid-year population estimates.
+1% since 2011: slower than 79% of UK towns
ONS mid-year estimates, each year indexed to mid-2011 = 100. Treherbert’s figure is the small areas (2021 LSOAs) that make up the town.
People, mid-2011 = 100
Change by age, 2011 to 2024
About 5,700 people in 2011; 5,800 in 2024.
In one year, mid-2018 to mid-2019, the population rose by 60, the most of any year. Growth was strongest among the 30 to 44 (+20%) and weakest among the 16 to 29 (−17%).
Treherbert is younger than 62% of UK towns: a median age of 43
Share of residents in each five-year age band, Census 2021.
There is little gap on residents aged 15 to 24: 12%, about the same as across Wales’s towns. The biggest five-year age group is 55–59, with 7.9% of residents. Fewer residents aged 65 and over than in just over half of UK towns: 22%.
Median age of UK towns of 2,500+
■ Treherbert, 43. The typical town is 44.4.
Broad ages · share of residents
Women and men · all residents
50% women, 50% men
About an even split. Across Wales, 51% of residents are women.
Treherbert ranks below 94% of UK towns on residents who moved in within the year: 6.4%
What adults did at the 2021 Census (the ONS’s NS-SEC classes), and where residents lived a year earlier.
Adults by occupation class · residents 16 and over
Address a year before the Census
Residents who lived somewhere else a year earlier. The bar runs to 25%.
In Treherbert, 18% of adults work in managerial and professional jobs and 36% in routine and semi-routine work, against 29% and 27% across Wales’s towns. The share of residents who moved in within the year across Wales’s towns is 9.1%. On the census count, 4.9% of adults are full-time students.
39% of households are one person living alone, more than in 98% of UK towns
Household make-up at the 2021 Census. Each square is 1% of households.
Against Mid Glamorgan’s towns and Wales’s towns
People per household
Wales’s towns.
1.7% of households are unrelated adults living together, against 3.1% across Wales’s towns. Against that, nearly a third of households are one person living alone across Wales’s towns. Average household size: 2.2 people. Few places have so few households with dependent children: 25% here, fewer than in 69% of UK towns.
A larger share of households without a car or van than 96% of UK towns: 31%
Accommodation type and cars or vans per household, Census 2021. Owning and renting are on Cost of living.
Type of home
Cars or vans · share of households
The share of households in flats is 9.2%, against 14% across Wales’s towns. Households without a car or van make up 21% across Wales’s towns.
3% of residents were born outside the UK, below 91% of UK towns
Country of birth, year of arrival and main language, Census 2021.
Born outside the UK, by region · share of all residents; the bar runs to 10%
When those born abroad arrived
Main language · residents aged 3 and over
Residents whose main language is English: 99%, above 91% of UK towns. Against that, 7.4% of residents were born outside the UK across Wales’s towns. By birthplace, the largest groups from abroad were born in EU countries (1.4%) and in the Middle East and Asia (0.8%).
Treherbert: 13% of residents speak Welsh
Welsh language skills, residents aged 3 and over, Census 2021.
Welsh language skills · residents aged 3 and over
707 residents, 13% of those aged 3 and over, said they can speak Welsh at the 2021 Census, against 16% across Welsh towns: more than in 61% of Welsh towns. Within Mid Glamorgan, Pontyclun has the largest share, 20%.
65% said they have no religion, more than in 99% of UK towns
How residents described themselves at the 2021 Census. Lines join the lowest and highest of the three figures.
Ethnic groups other than White British · all residents
White British, not charted: 97% of Treherbert · Mid Glamorgan’s towns 95% · Wales’s towns 90%.
Religion · all residents
28% of residents describe themselves as Christian, against 43% across Wales’s towns. The groups that follow White British are Other White (1.1%), Mixed or multiple (0.7%) and Indian (0.3%). Across Wales’s towns, 47% of residents said they have no religion.
More unpaid carers than 96% of UK towns: 12%
Legal partnership status (residents 16 and over) and unpaid care (residents 5 and over), Census 2021.
Partnership status · residents 16 and over
Unpaid care given · share of residents 5 and over
Across Wales’s towns, the share of adults who have never married is 38%; Treherbert has 39%. The share of unpaid carers across Wales’s towns is 10%. Unpaid care takes 50 hours a week or more for 240 people.
Among adults, 19% hold a degree-level qualification
Highest qualification, residents 16 and over, Census 2021.
Highest qualification · residents 16 and over
30% of Treherbert’s adults have no qualification (20% across Wales’s towns), and 19% have one at degree level (31%).
Of 516 UK towns its size (4,000 to 7,000 people), the 148th youngest
Median age, Census 2021. Hover a dot for its students and residents born abroad; click for its page.
Ages run from 18.9 in Bailrigg to 65.3 in Barton on Sea. Nearest to Treherbert in age: Potton (43), Llay (43), Blidworth (43.1) and Earls Barton (43.1).
Median age: 2 of the 7 towns around Treherbert are older
Nearby built-up areas coloured by median age, Census 2021. Tap a town for its page.
Health, work and homes have their own pages
What this data can and can’t tell you
- “Mid Glamorgan’s towns” and “Wales’s towns” mean their built-up areas. Census comparisons pool every built-up area in Mid Glamorgan (or Wales), summed the same way as Treherbert’s figures, so households in open countryside are left out. The population trend compares with the whole county and nation.
- Estimates since 2021 are modelled. The ONS builds mid-year estimates from the Census, births, deaths and migration records. Treherbert’s trend uses the small areas (2021 LSOAs) with most of their people inside it: 5,707 people in 2021, against 5,427 in the built-up area.
- Small counts are blurred. The ONS adds small random changes to Census counts to protect privacy, so the same total differs a little between tables, and the shares of a small town can move by a point or two.
Questions about Treherbert’s residents
What is the population of Treherbert?
The 2021 Census counted 5,427 people in Treherbert’s built-up area. The ONS estimates the same small areas held 5,800 people in mid-2024, 1% more than in 2011.
What is the average age in Treherbert?
The median age was 43 at the 2021 Census, younger than 62% of UK towns. 12% of residents were 15 to 24 and 22% were 65 or over.
How diverse is Treherbert?
97% of residents described themselves as White British in 2021, against 90% across Wales’s towns and 95% across Mid Glamorgan’s towns. 3% were born outside the UK.
What religion are people in Treherbert?
65% said they had no religion and 28% that they were Christian at the 2021 Census; 0.4% were Muslim and 5.7% didn’t answer.
Is Treherbert good for families?
25% of households had dependent children in 2021, against 27% across Wales’s towns. Schools are on Treherbert’s schools page.
How many people speak Welsh in Treherbert?
707 residents aged 3 and over, 13%, said they can speak Welsh at the 2021 Census, against 16% across Welsh towns.
Sources: ONS Census 2021, output areas summed to the ONS 2022 built-up area (TS002, TS003, TS004, TS007A, TS008, TS015, TS017, TS019, TS021, TS029, TS030, TS039, TS044, TS045, TS062, TS067, TS032) · ONS mid-year population estimates for 2021 LSOAs, mid-2011 to mid-2024. All under the Open Government Licence v3.0.
Contains public sector information licensed under the Open Government Licence v3.0. Contains HM Land Registry data © Crown copyright and database right 2026. Contains OS data © Crown copyright and database right 2026 (ONS boundaries). Northern Ireland: Source: NISRA; contains Land & Property Services data and Ordnance Survey of Northern Ireland information, © Crown copyright, licensed under the Open Government Licence v3.0. Scotland: contains National Records of Scotland data, Registers of Scotland data and SEPA data, © Crown copyright / © SEPA 2025, licensed under the Open Government Licence v3.0.