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Principal area · Wales

Cardiff

Discover Cardiff through its layered history, from Roman foundations and Norman fortifications to its growth as a port and its modern role as the Welsh capital.

Quick facts

Type of place
Principal area
Nation
Wales
Official identifier
gss:W06000015

Overview

Cardiff is a principal area in Wales and the Welsh capital. Coal exports helped transform an earlier riverside settlement into a major port. Its historical places include castle remains, medieval architecture and Victorian and Edwardian buildings, each showing a different part of the city’s past.

Cardiff is a principal area in Wales.

Population and demographics

Land area
140.91 km²

Figures for . ONS EW MYE25 workbook geography: Notes April 2024; landing edition 2023 boundaries.

Office for National Statistics · ons-mid-2025 · MYE5!D358 (binary spreadsheet decimal rounded to 6 dp). Released 29 July 2026.

Open Government Licence v3.0 · Source: Office for National Statistics licensed under the Open Government Licence v.3.0

Population
381,516 people

Figures for . ONS EW MYE25 workbook geography: Notes April 2024; landing edition 2023 boundaries.

Office for National Statistics · ons-mid-2025 · MYE2 - Persons!D358. Released 29 July 2026.

Open Government Licence v3.0 · Source: Office for National Statistics licensed under the Open Government Licence v.3.0

Population density: 2,707.4 people per km²

Calculated from the population and land area for 30 June 2025, using figures from the same release and covering the same boundaries.

Castle layers and medieval architecture

Cardiff Castle combines Roman foundations, Norman fortifications and Victorian interiors. Its keep, apartments and wartime shelters represent different uses of the site. Llandaff Cathedral retains medieval architecture, with the ruins of the medieval Bishop’s Palace nearby. These places add another strand to Cardiff’s architectural history alongside the castle.

Arcades and civic spaces

Cardiff’s Victorian and Edwardian shopping arcades include Castle Arcade, High Street Arcade and the Morgan Quarter. Their buildings form part of the city centre’s commercial history. Edwardian civic buildings and parkland provide another part of the city-centre setting, including City Hall and Alexandra Gardens. Together with the arcades, they offer a view of Cardiff beyond its earlier castle and medieval sites.

Sources

  1. History and heritage — Visit Cardiff. Cardiff Castle combines Roman foundations, Norman fortifications and Victorian interiors. (History and heritage). Accessed 2026-09-28.

  2. ONS local authority districts December 2025

    Office for National Statistics · lad-december-2025 · Open Government Licence v3.0 · Source: Office for National Statistics licensed under the Open Government Licence v.3.0 Contains OS data © Crown copyright and database right 2025.