The island of Ireland is split into 32 different counties, and from 1800 until 1921 the whole island was a part of the United Kingdome of Great Britain and Ireland (although Britain had been a controlling presence on the island for considerably longer than this). In 1921 the island was split into two separate states, where the six counties with the highest population of Protestants formed part of the United Kingdom of Great Britain and Northern Ireland, and the other 26 counties became the Independent Republic of Ireland. From 1821 until 1841, the population of these 26 counties was growing steadily, until the Great Famine from 1845 to 1849 swept across the island, particularly devastating the west and south.

The famine was caused by a Europe-wide potato blight that contributed to mass starvation and death throughout the continent, although it's impact on Ireland was much harsher than anywhere else. The potato blight affected Ireland so severely as the majority of potatoes in Ireland were of a single variety which allowed the disease to spread much faster than in other countries. People in the west and south of Ireland were particularly dependent on potatoes, and these areas were affected more heavily than the north and west, where flax and cereals were the staple. As the potato blight spread, the population became increasingly reliant on dairy and grain products, however a lot of these resources were relocated by the British military to combat food shortages in Britain. Due to disproportional dependency on potatoes, and mismanagement by the British government, over one million people died and a further one million emigrated. The Great Famine lasted from just 1845 to 1849, but it's legacy caused almost a century of population decline, and to this day, the population of Ireland has never exceeded it's pre-famine levels.

The population decline continued well into the twentieth century, during which time the Republic of Ireland achieved independence from the British Empire. After centuries of fighting and rebellion against British rule, Irish nationalists finally gained some independence from Britain in 1921, establishing an Irish Republic in the 26 counties. There was a lot of conflict in Ireland in the early 1900s, through the War of Independence and Irish Civil War, however the population of the Republic began growing again from the 1960s onwards as the quality of life improved and the emigration rate declined. The population was at it's lowest from 1926 to 1971, where it remained at just under three million, but in the following fifty years the population has grown by over two million people.

In 2025, there were 435,500 people aged between 40 and 44 in the Republic of Ireland, the most common age group among those provided in this year.

National and subnational mid-year population estimates for the UK and its constituent countries by administrative area, age and sex (including components of population change, median age and population density).

Usually resident population by ethnic or cultural background by Local Authorities. (Census 2022 Theme 2 Table 2 )Census 2022 table 2.2 is the population usually resident in Ireland by ethnic or cultural background. Details include population by ethnicity or cultural background. Census 2022 theme 2 is Migration, Ethnicity, Religion and Foreign Languages. The country is divided into 31 administrative counties/cities. Outside Dublin, there are 23 administrative counties and four cities: Cork, Limerick, Waterford and Galway. There are four local authority areas in Dublin: Dublin City and the three administrative counties of Dún Laoghaire-Rathdown, Fingal and South Dublin. The Local Government Reform Act 2014 Section 9 provided for the amalgamation of the city and county councils in Limerick, Waterford, and North Tipperary and South Tipperary County Councils.Coordinate reference system: Irish Transverse Mercator (EPSG 2157). These boundaries are based on 20m generalised boundaries sourced from Tailte Éireann Open Data Portal. This dataset is provided by Tailte Éireann, Administrative Counties 2019

In 2025, the population of the Republic of Ireland was approximately 5.46 million, with approximately 1.57 million people living in County Dublin, the region with the highest population.

In 2024, Belfast was the local district which had the highest number of inhabitants in Northern Ireland, with an estimated population of 352,390, followed by Armagh City, Banbridge and Craigavon which had approximately 222,511 people living there in this year.

Population by sex and marital status by Local Authorities. (Census 2022 Theme 1 Table 2 )Census 2022 table 1.2 is the total population of Ireland by sex and marital status. Details include population by sex and marital status. Census 2022 theme 1 is population by Sex, Age and Marital status. The country is divided into 31 administrative counties/cities. Outside Dublin, there are 23 administrative counties and four cities: Cork, Limerick, Waterford and Galway. There are four local authority areas in Dublin: Dublin City and the three administrative counties of Dún Laoghaire-Rathdown, Fingal and South Dublin. The Local Government Reform Act 2014 Section 9 provided for the amalgamation of the city and county councils in Limerick, Waterford, and North Tipperary and South Tipperary County Councils.Coordinate reference system: Irish Transverse Mercator (EPSG 2157). These boundaries are based on 20m generalised boundaries sourced from Tailte Éireann Open Data Portal. This dataset is provided by Tailte Éireann, Administrative Counties 2019

Analysis unit

Persons, households, and dwellings Age is grouped into categories; very short form

UNITS IDENTIFIED: - Dwellings: yes - Vacant Units: No - Households: yes - Individuals: yes - Group quarters: yes

UNIT DESCRIPTIONS: - Dwellings: no - Households: A private household is defined as a group of persons living together (usually but not necessarily related), jointly occupying the whole or part of a private dwelling house, flat, or temporary dwelling and sharing a common budget. A person who lives alone or a person who occupies only part of the living accommodation but does not normally share a common budget with the other occupants is regarded as a separate household. - Group quarters: A non-private household is a boarding house, hotel, guest house, barrack, hospital, nursing home, boarding schools, religious institution, welfare institution, prison, or ship, etc. However, proprietors and manager of hotels, principals of boarding schools, persons in charge of various other types of institutions and members of staff who, with their families, occupy flats on the premises are considered as private households.

Universe

All persons present in Ireland at the time of census, including visitors and those in residence. Usual residents temporarily absent from the State and members of the Defence Forces, who on Census night, were serving abroad with the United Nations were excluded.

Kind of data

Population and Housing Census [hh/popcen]

Sampling procedure

MICRODATA SOURCE: Central Statistics Office

SAMPLE SIZE (person records): 337686.

SAMPLE DESIGN: A 10% random sample of the recoded household records from each county was selected. The records within each county were sorted randomly before output to the sample file.

Mode of data collection

Face-to-face [f2f]

Research instrument

The information is based on Form A - Household Schedule.

Population estimates relate to the population as of 30th June each year, and therefore are often referred to as mid-year estimates. Population estimates for the 80 District Electoral Areas in Northern Ireland are presented by sex and broad age bands (0-15, 16-39, 40-64 and 65+) for mid-2011 to mid-2020.

Population by County, Year, Statistic and Social Class

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In 1821, Ireland's population was just over 6.8 million people. During this time, the entire island was a part of the United Kingdom of Great Britain and Ireland, after both islands were united by the Acts of Union in 1800. From the graph we can see that the population enjoyed steady growth between 1821 and 1841, and it rose by almost 1.4 million people in this time. However the Great Famine, which lasted from 1845 to 1849, had a devastating impact on the population, causing it to drop from 8.18 million in 1841 to 6.55 million in 1851. The Great Hunger The famine was caused by a Europe-wide potato blight that contributed to mass starvation and death throughout the continent, although it's impact on Ireland was much harsher than anywhere else. The potato blight affected Ireland so severely as the majority of potatoes in Ireland were of a single variety which allowed the disease to spread much faster than in other countries. As the potato blight spread, the population became increasingly dependent on dairy and grain products, however a lot of these resources were relocated by the British military to combat food shortages in Britain. Due to disproportional dependency on potatoes, and mismanagement by the British government, over one million people died and a further one million emigrated. The Great Famine lasted from just 1845 to 1849, but it's legacy caused almost a century of population decline, and to this day, the population of Ireland has never exceeded it's pre-famine levels. Road to recovery The population decline continued well into the twentieth century, during which time the Republic of Ireland achieved independence from the British Empire. After centuries of fighting and rebellion against British rule, Irish nationalists finally gained independence from Britain in 1921, although the six counties with the largest Protestant populations formed Northern Ireland, which is still a part of the United Kingdom today. In spite of the conflict that overshadowed Ireland for much of the twentieth century, which claimed the lives of thousands of people (particularly during the Northern Irish Troubles), and despite Ireland's high emigration rate, the population began growing again in the second half of the 1900s. The population was at it's lowest from 1926 to 1961, where it remained around 4.3 million, but in the following half-century the population grew by over two million people, reaching 6.4 million in 2011, although this number is still lower than in 1821. Gender stats The difference between the male and female populations throughout Ireland's recent history has also remained relatively low. The largest difference occurred in 1831, where there are 170,000 more women than men, although these figures do not include military personnel which would reduce the difference significantly. The gap then remains under 60,000 throughout the twentieth century.

Irish Travellers per 1000 of Total Population by Province County or City, CensusYear and Statistic

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Annual Rate of Population Increase by County, CensusYear, Statistic and Sex

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Counties Ireland 1911: 34 counties which includes thirty two counties and two urban areas of Belfast and Dublin.This boundary has been generated by aggregation and dissolving boundaries based on common value of County code. Slivers and gaps removed in this processing.The boundaries established for these areas were created from scanned maps and some boundaries were provided from other organizations who previously worked on this. Areas stated on the census tables were used to quality check the areas of each DED. There is no singular and accurate source for mapping representation available - this map is a best effort and indicative of location only.A special thanks to the open source OpenStreetMap (OSM) for providing data for Northern Ireland, and also to Mike Murphy at UCC who provided a map of Ireland at DED level that we could use to reference boundaries.Taillte Éireann provided 1911 boundary maps to the CSO with the following disclaimer: "This cartographic data is a digital representation of the 1911 ED and Poor Law Union datasets. It is for display purposes only and legal boundaries past or present cannot and should not be inferred from this map."OpenStreetMap shapefiles were provided in accordance with their copyright requirements.Scanned copies of Census 1911 Original Reports : Area, houses and population are available here Implements CSO classificationsC04131V04897 - Census 1911 County Classification number

This feature layer was created using Census 2016 data produced by the Central Statistics Office (CSO) and Administrative Counties national boundary data (generalised to 50m) produced by Tailte Éireann. The layer represents Census 2016 theme 11.2, population aged 5+ by time leaving home to travel to work, school or college. Attributes include a breakdown of population by time leaving for work, school or college (e.g. 6.30 - 7.00, 8.30 - 9.00). Census 2016 theme 11 represents Commuting. The Census is carried out every five years by the CSO to determine an account of every person in Ireland. The results provide information on a range of themes, such as, population, housing and education. The data were sourced from the CSO. In census reports the country is divided into 29 counties/administrative counties and the five Cities which represent the local authority areas. Outside Dublin there are 26 administrative counties (North Tipperary and South Tipperary each ranks as a separate county for administrative purposes) and four Cities, i.e. Cork, Limerick, Waterford and Galway. In Dublin the four local authority areas are identified separately, i.e. Dublin City and the three administrative counties of Dún Laoghaire-Rathdown, Fingal and South Dublin.

Percentage Change in Population by Province County or City, Statistic and CensusYear

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Population by Sex, Province County or City, Statistic and CensusYear

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This feature layer was created using Census 2016 data produced by the Central Statistics Office (CSO) and Administrative Counties national boundary data (generalised to 50m) produced by Tailte Éireann. The layer represents Census 2016 theme 3.1, population aged 3+ by ability to speak Irish. Attributes include population breakdown by ability to speak Irish (e.g. yes, no, not stated). Census 2016 theme 3 represents Irish Language. The Census is carried out every five years by the CSO to determine an account of every person in Ireland. The results provide information on a range of themes, such as, population, housing and education. The data were sourced from the CSO. In census reports the country is divided into 29 counties/administrative counties and the five Cities which represent the local authority areas. Outside Dublin there are 26 administrative counties (North Tipperary and South Tipperary each ranks as a separate county for administrative purposes) and four Cities, i.e. Cork, Limerick, Waterford and Galway. In Dublin the four local authority areas are identified separately, i.e. Dublin City and the three administrative counties of Dún Laoghaire-Rathdown, Fingal and South Dublin.

Population aged 3 years and over by ability to speak Irish by Local Authorities. (Census 2022 Theme 3 Table 1 )Census 2022 table 3.1 is population aged 3+ by ability to speak Irish. Details include population counts by ability to speak Irish. Census 2022 theme 3 is Irish Language. The country is divided into 31 administrative counties/cities. Outside Dublin, there are 23 administrative counties and four cities: Cork, Limerick, Waterford and Galway. There are four local authority areas in Dublin: Dublin City and the three administrative counties of Dún Laoghaire-Rathdown, Fingal and South Dublin. The Local Government Reform Act 2014 Section 9 provided for the amalgamation of the city and county councils in Limerick, Waterford, and North Tipperary and South Tipperary County Councils.Coordinate reference system: Irish Transverse Mercator (EPSG 2157). These boundaries are based on 20m generalised boundaries sourced from Tailte Éireann Open Data Portal. This dataset is provided by Tailte Éireann, Administrative Counties 2019

This feature layer was created using Census 2016 data produced by the Central Statistics Office (CSO) and Administrative Counties national boundary data (generalised to 50m) produced by Tailte Éireann. The layer represents Census 2016 theme 12.3, population by general health. Attributes include a breakdown of population by health status and sex (e.g. very good - males, fair - females, very bad - total). Census 2016 theme 12 represents Disability, Carers and General Health. The Census is carried out every five years by the CSO to determine an account of every person in Ireland. The results provide information on a range of themes, such as, population, housing and education. The data were sourced from the CSO.In census reports the country is divided into 29 counties/administrative counties and the five Cities which represent the local authority areas. Outside Dublin there are 26 administrative counties (North Tipperary and South Tipperary each ranks as a separate county for administrative purposes) and four Cities, i.e. Cork, Limerick, Waterford and Galway. In Dublin the four local authority areas are identified separately, i.e. Dublin City and the three administrative counties of Dún Laoghaire-Rathdown, Fingal and South Dublin.