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This section looks at the change in the population over time. Figure 1.1 shows the number of people in Ireland in each census year from 1901 to 2022 and uses mid-year estimate data for the corresponding year in Northern Ireland.
The census conducted on 18 April 1926 was the first census after the establishment of the Irish Free State in 1922. The population was 2.97 million having fallen by over 5% since the 1911 census continuing the decline that began after the Great Famine.
The census in 1961 marked the lowest recorded population in Ireland at just 2.82 million. The population in Northern Ireland experienced strong growth around this time, increasing by over 20% from 1.25 million in 1926 to 1.54 million in 1971.
Ireland's population began to increase again in the 1970s as emigrants returned and Ireland experienced positive net migration. The birth rate also increased, peaking in 1980. In comparison, in Northern Ireland there was a slight fall in the population in the 1970s.
However, emigration from Ireland increased again in the 1980s and the birth rate started to fall which led to a slight fall in the population between 1986 and 1991. In the 1990s the population started to increase again driven by high immigration, particularly after the enlargement of the EU in 2004. By 2010 the birth rate was increasing again and offset the high levels of emigration experienced after the financial crash. Most recently, immigration was a factor in the strong population growth between the 2016 and 2022 census.
Overall, despite volatile migration flows, the population in Ireland increased by 73% since 1926 to 5.15 million in 2022. In Northern Ireland the population increased by 52% over the same period to 1.91 million in 2022.
Visit Historical data on births, deaths and marriages for detailed tables.
The population pyramid in Figure 1.2 compares the age and sex structure of Ireland’s population in 1926 and 2022, using five‑year age groups. It illustrates the significant shift in the population’s age profile.
In 1926 the population had a more classic pyramid shape reflecting high fertility and lower life expectancy. In 2022 the pyramid had two bulges as a result of a cyclical trend where immigration and a ‘baby boom’ in the late 1970s was followed by emigration and falling birth rates in the late 1980s and this cycle was repeated in the 2000s.
The crude birth rate in 1926 was 20.6 births per 1,000 population, almost twice as high as the birth rate of 10.5 per 1,000 population in 2022. This is reflected in the age profile of population with over 29% of the population aged under 15 in 1926 compared with less than 20% of the population in 2022.
In 1926, life expectancy at birth was 57 years for males and 58 years for females. By 2022 life expectancy at birth was 81 years for males and 84 years for females. In 2022, 7% of the population was aged 75 and over, compared with almost 3% in 1926.
See Irish Life Tables, 1926 to 2012 for more information.
Map 1.1 looks at the population in Ireland in 1926 and 2022 at county level.
In 1926, 17% of the population were living in Dublin, with 12% in Cork, 6% in Mayo, 6% in Galway and 5% in Donegal.
By 2022, 28% of the population were living in Dublin, 11% in Cork, 5% in Galway, 5% in Kildare and 4% in Meath. This shift reflects the long‑term concentration of population in and around Dublin, driven by sustained urban growth, higher inward migration to the capital, and strong population increases in commuter counties such as Kildare and Meath.
Map 1.2 looks at the population change in Ireland since 1926 at county level. The map highlights the strong expansion of the eastern region, particularly the counties surrounding Dublin, alongside continued population decline in parts of the west and northwest.
The largest population growth by far was in Kildare where the population increased by 327% from 58,028 in 1926 to 247,774 in 2022, followed by Meath with an increase of 251%, and Dublin with an increase of 188%.
In contrast the populations of Leitrim (-37%), Mayo (-20%) and Roscommon (-16%) saw double digit decreases.
Figure 1.3 looks at the percentage change in population in Ireland from 1911 to 1926 at county level. The chart reveals a nationwide decline in population during this period, while also indicating a noticeable shift towards Dublin as the only area of growth.
Map 1.3 displays the distribution of percentage change in population from 1911 to 1926 for the 26 counties of Ireland at District Electoral Division (DED) level. A DED is a small administrative unit used in Ireland, originally established in the 19th century for organising local government and conducting censuses. Today, DEDs are known as Electoral Divisions (EDs). While DEDs were used extensively in the 1891, 1901, and 1911 censuses they were also used in Census 1926. The CSO has developed interactive DED maps to present the census data at a more granular level. The darker colour on the map represents a higher population with lighter colours representing lower population numbers.
While the 1911 data covered the entire island, the 1926 map focuses on the 26 counties, with Northern Ireland demarcated separately. To facilitate research, a unique system of geocodes and geolabels has been applied to the 1911 (HCA) and 1926 (HCA1926) digitised PxStat tables. The period between 1911 and 1926 represents a time of profound demographic and political shift in modern Irish history. Spanning the Great War, the 1916 Rising, the Irish War of Independence, Partition, and the Civil War, these fifteen years saw the birth of the Irish Free State (Saorstát Éireann) in 1922.
The 1926 Census, which was the first of the new state, provides insights into life in Ireland during this transition. The period was marked by a significant population decline in the 26 counties which is detailed in the bullet points below.
Out of 3,048 DEDs in the 1926 Census, only 596 (20%) showed a population increase and 11 showed no change, while 2,441 (80%) experienced a decline.
Kilbride DED, Baltinglass No 1 Rural District, Co Wicklow experienced a 45% decrease (747 to 414 people).
Bundoran DED, Bundoran Urban District, Co Donegal saw a 37% decline (2,116 to 1,339 people), likely impacted by the introduction of new customs and checkpoints at the border.
Some rural areas saw large population growth, such as Owennadornaun DED, Co. Mayo (175%) and Ballyglass DED, Co. Clare (138%). These were often the result of land redistribution schemes or the establishment of new infrastructure projects.
Queen’s County was renamed Laoighise, and King’s County became Offaly. Queenstown in Cork became Cobh, which was once a Victorian port, and Kingstown in Dublin was renamed Dun Laoghaire.
Some urban and rural districts boundaries were restructured to accommodate physical growth. For example, Graigue Urban DED was moved from Baltinglass No. 2 Rural District into the Carlow Urban District.
The departure of British forces caused significant decline in garrison towns. For example, Newbridge Urban DED in Kildare saw its population fall by 34% (from 3,400 to 2,249 people) as barracks transitioned to the Irish Free State.
Map 1.4 displays the distribution of population for 1891, 1901, and 1911 for the 32 counties of Ireland at DED level.
Census 1911 highlighted the shift in Ireland’s demographic landscape in the decades leading up to Ireland’s independence in 1921 and the establishment of the Irish Free State in 1922. While rural districts faced a persistent downward trend in population, the data reveals a significant countertrend of intense urban and suburban growth at this time. The period was defined by a massive internal migration away from the Atlantic seaboard and toward the industrial, maritime, and administrative hubs of the East and North-East.
Belfast functioned as the island’s primary economic engine, with growth and industrial output often surpassing Dublin.
Driven by global leads in shipbuilding and textiles, Pottinger Ward (Belfast) became the most populous DED in Ireland with 39,173 residents by 1911.
Larne DED (Antrim) grew by over 50% between 1891 and 1911 (5,259 to 8,036 people), reflecting the expansion of industrial port towns. Lurgan Urban District (Armagh) recorded a 10% over the same period.
Ballyhackamore DED grew from 356 to 1,222 residents, a 243% increase, marking the rapid transformation of the Belfast periphery.
The concentration of administrative and professional sectors led to the early development of a metropolitan commuter belt on the capital’s periphery.
Donabate DED (Dublin) experienced a 242% growth in population between 1891 and 1911 (734 to 2,508 people), largely driven by state infrastructure and the opening of the Portrane institutional complex.
Terenure DED transitioned from a semi-rural village to a residential hub, expanding by 64% between 1891 and 1911 (3,313 and 5,437 people), facilitated by the Dublin United Tramways system which allowed residents to work in the city centre while residing in suburban areas.
The population of the Atlantic seaboard continued to reflect the long-term effects of post-Famine emigration, as many people in the West moved toward growing cities in the East or left the country entirely.
Sharp declines were recorded in Toberpatrick West (Sligo) at 39%, Crossboyne DED Mayo at 38%, and Cong (Mayo) at 33% (1,455 to 973 people) between 1891 and 1911.
Amidst rural decline, strategic railway and market towns acted as regional urban centres, providing the administrative network that eventually served as the foundation for the Irish Free State.
Dundalk Urban District (Louth) recorded consistent growth across the period, with the South Ward expanding by 31% between 1891 and 1911 (2,631 to 3,454 people), reflecting its role as a key commercial and railway hub on the east coast.
Athlone East Urban DED (Westmeath) recorded a 18% increase in population over the same period (3,240 to 3,812 people), consolidating its role as the dominant crossing point on the Shannon.
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