Historic Parliamentary Boundaries of Wales

In the past, Members of Parliament (MPs) represented either a town (referred to historically as a ‘Burgess’ or ‘Borough’) or a county. Between 1660 and 1832, the electoral system became increasingly unfair and open to corruption. Small towns consisting sometimes of only a handful of eligible voters could, due to minimal changes to the electoral system, appoint not just one but two MPs. These became known as Rotten Boroughs. As small places with no parliamentary representation grew in the wake of the movement of people during the industrial revolution, the system became very unbalanced. There were also the ‘Pocket Boroughs’ where wealthy aristocrats where able to exert control to get their preferred candidates elected. The ‘Great Reform Act’ of 1832 did much to improve the representation and another act in 1867 made further improvements. As the County series mapping in Wales begam shortly after 1867 the maps depict the parliamentary boundaries as determined by this act. Parliamentary boundaries continued to cover more of the country and change as the population grew and electoral reform gave the vote to more people. The process still continues today, with the last changes being as recent as 2023.

The mapping of historical boundaries requires many sources to be consulted. The most important has been the large scale first edition Ordnance Survey County Series mapping. The first edition six-inch to the Mile (1:10,560) scale mapping has been digitised by the National Library of Scotland (NLS) and this has provided a reliable source to map the boundaries from. As the project progresses, larger-scale sources such as the 25-inch (1:2,500) scale Ordnance Survey mapping will be used to refine the boundaries. Earlier cartographic sources will also be consulted such as Enclosure and Estate mapping and the Welsh Tithe Maps digitised by the National Library of Wales.

All of the digital boundary datasets have been made available for public use under the Open Government Licence for public sector information. This means that you are free to copy, publish, distribute and adapt the information. We ask that when using this information that you acknowledge where this information has come from using the following accreditation:

‘© Crown Copyright, Royal Commission on the Ancient and Historical Monuments of Wales available under Open Government License 3.0’

‘© Crown Copyright, RCAHMW available under Open Government License 3.0’

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Attributes (47)

Attribute name	Label	Description
Id
Senedd
Parliament
Trefgordd
Township
Plwyf
Parish
SaesonCant
Hundred
Sir
County
Rhanbarth
Region
ErwHanes
HisAcre
ErwModern
ModAcre
DyddArolwg
SurveyDate
SymMap
MapSym
Ffynhonnel
Source
Sefydliad
SourceOrg
Cyswllt
SourceLink
Nodiadau
Notes
Hawlfraint
Copyright
DigidoGan
DigitiseBy
DigidolOrc
DigiOrcid
DigidolAr
DigitiseOn
PriodolGan
AttriBy
PriodolOrc
AttriOrcid
PriodolAr
AttriOn
Methodoleg
Method
Cywirdeb
Accuracy