The first all Ireland Government census was taken  in 1821 and with few exceptions, every 10 years there after. In 1917, one year after the Easter Rising, the British Government, in its wisdom, and for dubious reason, i.e. "The War Effort", ordered that the Irish census for the years 1861, 1871, 1881 and 1891, should be pulped, and in so doing, destroyed, and deprived the Irish people of a precious part of our Irish National Heritage. The census for 1841 and 1851 were spared this fate, because the Government used them to prove the ages of applicants for the Old Age Pension. Ironically, during the Irish Civil War in 1922, the Republican side took over the Four Courts in Dublin, the repository for the Public Records Office of Ireland, and were bombarded by the Free State side, setting fire to the building and destroying, along with the Church of Ireland records, the census for 1821, 1831, 1841 and 1851. The tragedy for the Irish people and her descendants, of loosing four census "for war" and four census "to war", be it deliberately or accidentally, can not be over stated. The facts of the matter are that, except for a few surviving remnants, Ireland lost eight, irreplaceable 19th century census in six years. It is for this reason that the Irish Government lifted the normal 100 year embargo on census, and opened to the public, the 1901 and 1911 census after 80 and 70 years respectively. Be thankful for little mercies.

1821 census.
This census was taken on 28 May 1821 and was organized by townland,  parish, barony and county. The information included the name, age, occupation relationship to head of household, acreage and number of stories of the house. Virtually all of the original returns were destroyed in 1922 except for a few surviving remnants for Counties Armagh ,Cavan, Fermanagh, Galway, Meath and Offaly.

1831 census.
This census was organized by townland,  parish, barony and county. The information included the name, age, occupation relationship to head of household, acreage and religion. Nearly all of the original returns were destroyed in 1922 except for a few surviving remnants for County Derry.

1841 census.
This census was taken on 6 June 1841 and was organized by townland,  parish, barony and county. The information included the name, age, occupation, date of marriage, relationship to head of household, literacy, absent family members and family members who had died since 1831. Only one complete set of original returns, for the Parish of Killeshandra in County Cavan, survived 1922.

1851 census.
This census was taken on 30 March 1851 and was organized by townland,  parish, barony and county. The information included the name, age, occupation relationship to head of household, date of marriage, literacy, absent family members and family members who had died since 1841 and religion. The only surviving original returns of this census relate to a number of Parishes in County Antrim, and a list of heads of households named in the returns for Dublin City.

1861 census.
The destruction of this census by the British Government was so thorough that none of the original returns survive. However there is a transcript of this census for Catholics in the Parish of Enniscorthy County Wexford in the Catholic record for that parish.

1871 census.
The destruction of this census by the British Government was so thorough that none of the original returns survive. However there is a transcript of this census for Catholics in the Parishes of  Drumcondra and Loughbraclen in County Meath in the Catholic record for those parishes.

1881 census.
The destruction of this census by the British Government was so thorough that none of the original returns survive. 

1891 census.
The destruction of this census by the British Government was so thorough that none of the original returns survive. 

1901 census.
This census was taken on 31 March 1901 and was organized by Poor Law Union, District Electoral Division, county, barony, parish, townland, ward and street, in town or city. The information included the name, relationship to head of household, religion, literacy, occupation, age, marital status, county of birth and ability to speak English or Irish. The census survives for all 32 counties.

1911 census.
This census was taken on 2 April 1911 and was organized by Poor Law Union, District Electoral Division, county, barony, parish, townland, ward and street, in town or city. The information included the name, relationship to head of household, religion, literacy, occupation, age, marital status, number of years married, number of children born alive to this marriage, number of children still living on 2 April 1911, county of birth and ability to speak English or Irish. The census survives for all 32 counties.

Census Substitutes and Other Census.
Any list of names, accompanied by a location and date, can be considered as a census of that location at that point in time, and there were other census taken for different purposes in Ireland since the early 17th century.

Hestings Manuscripts 1612 to 1613.
A list of English and Scottish landlords granted large estates of land in Counties Cavan, Donegal and Fermanagh.

Muster Rolls 1630.
Lists of large landlords in Ulster with the names of the able-bodied men they could muster to fight.

Book of Survey and Distribution 1641.
A record of land ownership before 1641 and after 1704.

The Civil Survey 1655 to 1667.
A record of land ownership. Only some counties

Penter's Census 1659.
It gives the names of titulates (i.e. those with title to land). The number of persons (English and Irish) resident in each townland and the principal Irish names in each barony are also listed.
Only some counties.  

Subsidy Rolls 1662 to 1666.
List of nobility, clergy and others who grant-aided the King.

Hearth Money Rolls 1664 to 1666.
A tax based on the number of hearths or fireplaces in a house.

Religious Census 1766.
This was drawn up by each Church of Ireland rector and lists all householders in his parish, along with any information on Catholic clergymen active in the Parish. 

Spinning-wheel Premium 1796.
A list of those entitled to free spinning-wheels or looms for growing a ¼ acre or more of land with flax.

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