Photo: Jaggery · CC BY-SA 2.0In Ynysybwl, 50% of households live in a terraced house, more than in 98% of UK towns
Christians make up 38% of residents, against 43% across Wales’s towns. Here, just over one in ten residents give unpaid care. Compared with other places, households in flats are scarce here: 6.1%, fewer than in 78% of UK towns. Census day 2021: 4,580 residents and 1,957 households in Ynysybwl.
What the Census says about Ynysybwl’s people
Fewer people than in 2011
ONS mid-year estimates put Ynysybwl at 4,700 in 2011 and 4,600 in 2024, down 1%, against 4% for Wales: slower growth than in 89% of UK towns. Since 2011 ↓
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.
Ynysybwl’s population moved −1% on 2011, less than in 89% of UK towns
ONS mid-year estimates, each year indexed to mid-2011 = 100. Ynysybwl’s figure is the small areas (2021 LSOAs) that make up the town.
People, mid-2011 = 100
Change by age, 2011 to 2024
About 4,700 people in 2011; 4,600 in 2024.
Split by age, the 65 and over changed most (+14%) and the 0 to 15 least (−13%).
A median age of 42: Ynysybwl is younger than 69% of UK towns
Share of residents in each five-year age band, Census 2021.
At 12%, residents aged 15 to 24 sit close to the figure across Wales’s towns. Ynysybwl has fewer residents aged 65 and over than 72% of UK towns, at 19%. No age band is larger than 55–59: 7.9% of residents.
Median age of UK towns of 2,500+
■ Ynysybwl, 42. The typical town is 44.4.
Broad ages · share of residents
Women and men · all residents
51% women, 49% men
About 95 men for every 100 women. Across Wales, 51% of residents are women.
5.9% of residents lived at another address a year earlier, fewer than in 97% of UK towns
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%.
5.4% of adults are full-time students, against 8% across Wales’s towns. The share of residents who moved in within the year across Wales’s towns is 9.1%.
The Census was taken on 21 March 2021, in term time, so students were counted at their term addresses.
In Ynysybwl, 29% of households have dependent children, more than in 67% 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.
In Ynysybwl the average household is 2.3 people, beside 2.3 across Wales’s towns. The census found that 2.2% of households are unrelated adults sharing a home here. Measured more widely, 27% of households have dependent children across Wales’s towns.
Ynysybwl sits below 78% of UK towns for households in detached houses (18%)
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
Where 21% of households have no car or van across Wales’s towns, Ynysybwl has 18%. Across Wales’s towns, households in detached houses come to 24%.
Ynysybwl sits below 94% of UK towns for residents born outside the UK (2.8%)
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
By birthplace, the largest groups from abroad were born in EU countries (1.5%) and in the Middle East and Asia (0.8%). 99% of residents have English as their main language, a higher share than in 81% of UK towns. Measured more widely, 7.4% of residents were born outside the UK across Wales’s towns. Recent arrivals (2017 or later) make up 17% of those born abroad (Wales’s towns: 23%).
Welsh speakers: 16% of Ynysybwl’s residents
Welsh language skills, residents aged 3 and over, Census 2021.
Welsh language skills · residents aged 3 and over
Asked in 2021, 688 residents aged 3 and over, 16%, said they can speak Welsh; across Welsh towns, 16%: more than in 68% of Welsh towns. Pontyclun leads Mid Glamorgan with 20%.
A larger share of residents with no religion than 98% of UK towns: 55%
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: 96% of Ynysybwl · Mid Glamorgan’s towns 95% · Wales’s towns 90%.
Religion · all residents
90% of residents describe themselves as White British across Wales’s towns, against 96% in Ynysybwl. The next-largest groups, after White British, are Other White (1.3%), Mixed or multiple (1.1%) and Indian (0.2%). The comparison figure for residents with no religion is 47% across Wales’s towns.
In Ynysybwl, 37% of adults have never married or formed a civil partnership, more than in 78% of UK towns
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
44% of adults are married or in a civil partnership, against 43% across Wales’s towns. The share of adults who have never married across Wales’s towns is 38%.
The share of adults with a degree-level qualification: 26%
Highest qualification, residents 16 and over, Census 2021.
Highest qualification · residents 16 and over
23% of Ynysybwl’s adults have no qualification (20% across Wales’s towns), and 26% have one at degree level (31%).
Of 695 UK towns its size (3,000 to 6,000 people), the 132nd youngest
Median age, Census 2021. Hover a dot for its students and residents born abroad; click for its page.
The youngest is Bailrigg (18.9) and the oldest Sutton on Sea and Trusthorpe (64.7). Nearest to Ynysybwl in age: South Darenth and Sutton at Hone (41.9), Highbridge (42), Calverley (42.1) and Havercroft and Ryhill (42.1).
Older than Ynysybwl: 3 of the 7 towns nearby
Nearby built-up areas coloured by median age, Census 2021. Tap a town for its page.
| Town | People | Away | Median age | 65+ | Homes with children |
|---|---|---|---|---|---|
| Ynysybwl | 4,580 | — | 42 | 19% | 29% |
| Abercynon | 6,376 | 1.6 mi | 39.2 | 17% | 30% |
| Porth | 13,352 | 2.6 mi | 42.7 | 20% | 25% |
| Wattstown | 1,105 | 2.7 mi | 38.9 | 17% | 31% |
| Pontypridd | 31,895 | 2.8 mi | 37.3 | 17% | 26% |
| Treharris | 5,042 | 2.9 mi | 44.4 | 21% | 26% |
| Mountain Ash | 13,002 | 3.2 mi | 41.2 | 19% | 29% |
| Nelson | 4,235 | 3.2 mi | 48.6 | 26% | 25% |
Health, work and homes have their own pages
What this data can and can’t tell you
- The Census was taken in a lockdown, in term time. 21 March 2021 fell in term time, and students were asked to give their term-time address, so most were counted where they study. Some may have been living with family that day.
- “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 Ynysybwl’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. Ynysybwl’s trend uses the small areas (2021 LSOAs) with most of their people inside it: 4,580 people in 2021, against 4,580 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 Ynysybwl’s residents
What is the population of Ynysybwl?
The 2021 Census counted 4,580 people in Ynysybwl’s built-up area. The ONS estimates the same small areas held 4,600 people in mid-2024, 1% fewer than in 2011.
What is the average age in Ynysybwl?
The median age was 42 at the 2021 Census, younger than 69% of UK towns. 12% of residents were 15 to 24 and 19% were 65 or over.
How diverse is Ynysybwl?
96% of residents described themselves as White British in 2021, against 90% across Wales’s towns and 95% across Mid Glamorgan’s towns. 2.8% were born outside the UK.
What religion are people in Ynysybwl?
55% said they had no religion and 38% that they were Christian at the 2021 Census; 0.4% were Muslim and 5.5% didn’t answer.
Is Ynysybwl good for families?
29% of households had dependent children in 2021, against 27% across Wales’s towns. Schools are on Ynysybwl’s schools page.
How many people speak Welsh in Ynysybwl?
688 residents aged 3 and over, 16%, 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.