There are many different territorial classifications used in statistics. While these classifications are all based on geography, they may not necessarily link together easily as they may have evolved differently for different purposes or be based on different parameters. Some geographies are based on administrative breakdowns, either historical or current, while others have been developed specifically for statistical purposes. Because these geographies have often been developed separately, it is not always possible to integrate them easily. It is important to note that, with many geographical classifications, boundaries change over time and such changes should be clearly displayed and labelled in a classification to minimise potential confusion.
The following page outlines some of the most commonly used geographical classifications and how they can be interlinked.
The overarching framework for regional and territorial statistics in the European Statistical System is the Nomenclature of Territorial Units for Statistics (NUTS). NUTS is a classification of statistical geography that supports the collection, development, and harmonisation of European regional statistics. NUTS is a hierarchical classification subdividing the EU into geographical blocks that facilitate comparison and is used for framing of EU regional policies including the identification of regions eligible for support from EU cohesion policy.
Across the EU NUTS, lists 92 regions at NUTS 1 level, 244 regions at NUTS 2 and 1 165 regions at NUTS 3 level. Ireland consists of 1 region at NUTS 1 (state), 3 regions at NUTS 2 and 8 regions at NUTS 3 level.
NUTS divisions are based on three key principles:
The Eurostat Statistical Atlas of NUTS and territorial typologies provides a useful visualisation of NUTS for Ireland and at European level.
Historically, the island of Ireland was divided into four regions called provinces. These provinces were Munster (6 counties), Leinster (12 counties), Connacht (5 counties), Ulster (9 counties). With the partition of Ireland in 1921, six of the nine Ulster counties formed Northern Ireland while the remaining three became part of Ireland. Provinces no longer have any administrative or political purpose, do not align with NUTS, and are used very infrequently in CSO statistics.
The counties of Ireland are a sub-division of Ireland into twenty-six units or a sub-division of the island of Ireland into thirty-two units based on historic administrative divisions. While counties are no longer used for administrative purposes, they retain significant historical and cultural interest. They also closely align with current administrative sub-divisions (see Local Authority Area classification) and NUTS. Further information is available in the CSO County and NUTS Regions classification.
Local authorities are the primary units of administration at a local level within Ireland operating within specific geographical areas, strongly associated with the historical counties. Local Authority area closely align with NUTS. Further information is available in the CSO Local Authority and NUTS Regions classification.
Under Local government legislation the Minister for Housing, Planning and Local Government is responsible for dividing each city, county, and city and county into local electoral areas. Each city and county local authority is divided into Local Electoral Areas (LEAs). LEAs and the number of members to be elected in each are specified in a statutory instrument for each local authority area. In general, LEAs are formed by aggregating Electoral Divisions. CSO Local Electoral Areas (LEAs) 2022 is a statistical geography breakdown that aligns closely with the official LEA boundary, but which may include adjustments for statistical reasons, such as to prevent statistical disclosure.
To meet the demand for statistics at a local level, Eurostat maintains a system of local administrative units (LAUs) compatible with NUTS. These LAUs are the building blocks of the NUTS, and comprise the municipalities and communes of the European Union. Local Administrative Units is a terminology used in the European Statistical System. In Ireland, LAUs are equivalent to Local Electoral Areas (LEAs).
Electoral Divisions (EDs) are the smallest legally defined administrative area in the state. EDs originated as subdivisions of poor law unions (Poor Relief (Ireland) Act 1838). In Dublin, the current EDs (formerly District Electoral Divisions and Wards) were redrawn under S.I. 12/1986 & S.I. 12/1986. Wards and DEDs became known as EDs under the 1994 Local Government Act. In general, EDs were formed by aggregating townlands. EDs in turn are combined to create Local and National Constituencies. There are currently 3,440 Electoral Divisions. For further information see Tailte Éireann.
In order to render the legally defined Electoral Divisions suitable for production of statistics, the CSO may, on occasion, amend some ED boundaries to ensure that statistical disclosure does not occur. This has had the effect of amalgamating some EDs and splitting others. For example, in the classification CSO Electoral Divisions, 2022, the amending of the Cork City and Cork County boundaries necessitated a redrawing of Electoral Division boundaries within Cork to ensure all EDs in the county were suitable for production of statistical data. For Census 2022, the CSO is publishing data for 3,420 Electoral Divisions.
Small Area Population Statistics are statistics produced for a range of geographical levels from State to Small Areas. They are designed as the lowest level of geography for the compilation of statistics in line with data protection guidelines and typically contain between 50 and 200 dwellings. Small area data can be accessed through the CSO Interactive Mapping Tool or through Census data tables. Small area data can also be downloaded as csv files.
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