A census of the Irish Free State was held on 18 April 1926. A parallel census for Northern Ireland was held the same day. These were the first Irish censuses since the partition of Ireland of 1920–1925. The previous all-island census had been in 1911; the decennial census due in 1921 was cancelled because the revolutionary Irish Republic had urged a boycott of it as being a project of the Dublin Castle administration it was fighting in the Irish War of Independence.Linehan 1997–1998 pp.53–54 The 1926 Free State data was made freely accessible online on 18 April 2026, the centenary of the census.

Organisation The General Register Office (GRO) had organised earlier Irish censuses.Linehan 1997–1998 pp.49, 63 After the Free State was established in December 1922, several advisory committees of civil servants and academics from 1923 to 1925 advised the Cumann na nGaedheal government on what statistics the new state needed and how they should be gathered.Linehan 1997–1998 pp.55–62 The plan agreed by 1925 was for the GRO to organise the following year's census of population under an amended version of previous statutes, with a separate census of production to be organised by the Statistics Branch of the new Department of Industry and Commerce under a new statute.Linehan 1997–1998 pp.63–64 Delay in preparation meant that a single generic statute, the Statistics Act 1926, was passed by the Free State Oireachtas to empower the Statistics Branch to organise both censuses, with the census of production delayed to 1927. The population census was actioned by a ministerial order made under the 1926 act by Patrick McGilligan, the Minister for Industry and Commerce.McGilligan 1926 The Statistics Branch consulted the GRO for its institutional memory of previous censuses. In December 1925 the Craigavon ministry had chosen 18 April 1926 for the census in Northern Ireland, so the Free State government chose the same date.

There were two primary forms: FormA, for each household, to be completed by the "head of household"; and FormB, for aggregating all the households and unoccupied houses in an enumeration area, to be completed by the enumerator. Enumerators were members of the Garda Síochána, who distributed Form A's in the week preceding Census Day and collected them in the following days.McGilligan 1926 s.3(b) The enumeration area was the townland in rural areas and street in urban areas. The questions to be asked on the forms were decided in consultation with the advisory committee on statistics.

Form A questions relating to individuals:McGilligan 1926, Schedule, Form A retained from earlier censuses: name and surname; relation to head of household (spouse, stepson, servant, lodger, visitor, etc); sex; marital status; religion; occupation; and number of children of current and of any previous marriage. asked in greater detail: age in months as well as years; knowledge of Irish (as native or second language, spoken or written); birthplace (town or townland rather than merely county). new: employees were asked name and business of the employer; under-16s were asked which parents were still living. dropped in 1926: illiteracy (which was felt to have become confined to the elderly); disability (blindness, deafness, mutism and learning disability; previous censuses had significant underreporting).

Besides details of individuals, FormA also requested the size in statute acres of any agricultural holdings associated with the household. Form B included details of all buildings in the area—classed as multi-household, single-household, unoccupied residential, and non-residential—with for each household the number of males, females, and rooms occupied.McGilligan 1926, Schedule, Form B

Publicity to encourage co-operation was solicited from Catholic and Protestant clergy, chambers of commerce, trade unions and professional associations, and national school teachers.Lyon 1934 pp.5–6 Instructions on completing the form were broadcast on 2RN on 17 April and 18 April. Sinn Féin told its supporters to complete the census form, an exception to its usual advocacy of noncooperation with the institutions of the Free State, whose legitimacy it denied.

For the first time, the census forms were printed in Irish as well as English (on opposite sides of the same sheet). Less than 1% of respondents filled in the Irish-language side.

Statistics Each enumerator completed a separate FormC summarising all data from the FormsA and B they had gathered. A preliminary report was published in August 1926 by tabulating the FormC returns. The total recorded population was 2,971,992; down from the 3,139,688 recorded for the equivalent area in the 1911 census.

The FormA and B data was transcribed to punched cards by 21 "girls" and input into tabulating machines by "12 male clerks assisted by 12 junior male clerks". Detailed results generated from this were reported in nine thematic volumes published between 1928 and 1933 and a tenth volume in 1934 analysing the data of the previous nine.Lyon 1934 p.iv Maps were produced in co-operation with the Ordnance Survey of Ireland. Whereas censuses up to 1911 had reported rural data down to the townland level, to save expense the published 1926 census reports stopped at the level of the district electoral division (DED), which comprises multiple townlands. The larger reporting units built from DEDs were dispensary districts; urban and rural districts; administrative counties and county boroughs; and provinces. Although DEDs and (except in County Dublin) rural districts had ceased to be units with administrative functions, they were retained as convenient areas for aggregation of data and comparison with previous censuses. Basic population information was also provided for Dáil constituencies.

Religion

Compared with 1911, there was a small overall decline in the number of Catholics, with increases in some urban areas. The number of non-Catholics declined steeply, especially in western and southern areas, and places which formerly had British Army bases, such as the Curragh Camp in County Kildare. Thus, Catholics increased as a percentage of the overall population, from 89.6% to 92.6%.From 2,812,509 out of 3,139,688 in 1911 to 2,751,269 out of 2,971,992 in 1926:

+Numbers professing various religions at 1926 census, with percentage change (Δ) of each since 1911, and total non-Catholic percentage (%) Area Total Catholic Other denominations and religions Total AnglicanCalled "Protestant Episcopalian" in the Report; mainly Church of Ireland, some Church of England Presbyterian Methodist Jewish/Baptist/other Free State total 2,971,992 −5.3 2,751,269 −2.2 220,723 7.4 −32.5 164,215 −34.2 32,429 −28.7 10,663 −35.1 3,686 717 9,013 −14.6 Leinster total 1,149,092 −1.1 1,032,835 116,257 10.1 −32.4 92,899 −33.7 8,589 −33.2 5,564 −31.0 3,226 499 5,480 −15.4 Carlow 34,476 −4.9 31,487 −2.6 2,989 8.7 −24.0 2,719 −24.5 97 −20.5 106 −32.5 15 0 52 Dublin 316,693 285,033 31,660 10.0 −38.4 23,417 −40.5 2,658 −37.0 1,431 −38.4 2,450 170 1,534 −25.0 Dublin 188,961 149,026 39,935 21.1 −20.2 30,392 −22.7 3,641 −17.3 2,379 −12.2 700 247 2,576 −1.9 Kildare 58,028 −12.9 54,401 −0.5 3,627 6.3 −69.6 3,193 −69.6 223 −63.5 118 −79.5 12 19 62 −64.0 Kilkenny 70,990 −5.3 68,377 −4.0 2,613 3.7 −30.7 2,342 −30.2 108 −49.5 61 −15.3 5 0 97 −19.0 Laois 51,540 −5.7 46,880 −3.3 4,660 9.0 −24.2 4,193 −21.0 143 −49.3 214 −42.0 3 6 101 −42.4 Longford 39,847 −9.1 37,555 −6.8 2,292 5.8 −34.9 1,973 −36.0 121 −47.4 109 −33.1 0 0 89 Louth 62,739 −1.5 59,623 3,116 5.0 −41.9 2,295 −43.2 555 −40.6 147 −36.6 19 10 90 −22.2 Meath 62,969 −3.3 59,769 −1.5 3,200 5.1 −27.8 2,884 −26.9 181 −48.3 17 −69.1 4 1 113 Offaly 52,592 −7.5 48,705 −4.8 3,887 7.4 −31.3 3,409 −30.5 148 −58.1 205 −24.1 3 3 119 0 Westmeath 56,818 −5.3 54,208 −1.0 2,610 4.6 −49.9 2,301 −49.4 149 −56.4 69 −66.0 2 18 71 −18.8 Wexford 95,848 −6.3 90,136 −4.5 5,712 6.0 −27.3 5,119 −27.4 149 −41.3 216 −35.3 0 11 217 Wicklow 57,591 −5.1 47,635 −0.8 9,956 17.3 −21.7 8,662 −22.4 416 −25.3 492 −18.8 13 14 359 Munster total 969,902 −6.3 934,703 −4.0 35,199 3.6 −42.9 28,614 −43.5 1,601 −61.7 2,397 −42.6 439 186 1,962 −3.8 Clare 95,064 −8.8 93,942 −8.2 1,122 1.2 −41.9 833 −51.3 54 −67.5 6 −84.2 7 1 221 Cork 78,490 74,047 4,443 5.7 −49.8 3,102 −52.8 350 −61.6 394 −38.7 290 58 249 −18.0 Cork 287,257 −8.9 271,072 −6.0 16,185 5.6 −40.0 13,791 −40.0 468 −54.9 1,221 −40.4 72 38 595 −21.6 Kerry 149,171 −6.6 146,821 −5.5 2,350 1.6 −46.2 2,051 −44.9 104 −60.8 100 −62.3 3 9 83 −16.7 Limerick 39,448 37,640 1,808 4.6 −50.5 1,285 −44.5 147 −82.6 104 −51.2 30 38 204 −1.8 Limerick 100,895 −3.5 98,793 −2.7 2,102 2.1 −31.1 1,691 −33.7 65 −52.2 206 −24.5 3 10 127 Tipperary, North 59,645 −5.1 57,061 −3.7 2,584 4.3 −28.9 2,188 −31.4 39 −61.8 185 −23.2 0 0 172 Tipperary, South 81,370 −9.1 79,503 −6.4 1,867 2.3 −59.8 1,559 −61.3 134 −59.4 38 −80.4 7 1 128 Waterford 26,647 −3.0 25,466 1,181 4.4 −44.6 861 −43.7 124 −32.2 70 −49.6 27 20 79 −55.2 Waterford 51,915 −8.1 50,358 −6.8 1,557 3.0 −36.2 1,253 −38.2 116 −42.3 73 −40.2 0 11 104 Connacht total 552,907 −9.5 538,277 −8.5 14,630 2.6 −36.3 12,417 −34.7 976 −52.8 738 −44.2 11 12 476 −13.7 Galway 169,366 −7.1 167,347 −5.9 2,019 1.2 −53.1 1,673 −52.8 201 −59.4 64 −57.9 0 1 80 −28.3 Leitrim 55,907 −12.1 52,196 −10.3 3,711 6.6 −31.6 3,286 −30.0 89 −52.2 279 −45.3 1 2 54 Mayo 172,690 −10.1 170,211 −9.5 2,479 1.4 −39.7 2,066 −38.9 271 −47.4 66 −53.2 3 0 73 Roscommon 83,556 −11.1 82,210 −10.4 1,346 1.6 −39.5 1,147 −39.2 110 −43.6 18 −71.9 0 7 64 −10.1 Sligo 71,388 −9.7 66,313 −8.1 5,075 7.1 −26.7 4,245 −22.9 305 −55.0 311 −31.8 7 2 205 −23.8 Ulster () 300,091 −9.4 245,454 −5.8 54,637 18.2 −22.5 30,285 −23.7 21,263 −19.4 1,964 −31.7 10 20 1,095 −28.3 Cavan 82,452 −9.6 69,383 −6.6 13,069 15.9 −22.7 10,102 −22.0 2,196 −22.8 468 −40.1 6 2 295 −7.1 Donegal 152,508 −9.5 124,941 −6.1 27,567 18.1 −22.4 13,774 −23.6 12,162 −19.0 1,202 −29.2 1 15 413 −45.1 Monaghan 65,131 −8.9 51,130 −4.2 14,001 21.5 −22.6 6,409 −26.5 6,905 −18.9 294 −25.6 3 3 387 −14.6

Occupations