Abstract copyright UK Data Service and data collection copyright owner.The purpose of the project was to provide machine-readable economic and social history statistics relating to the whole of Ireland for the period 1821-1971. Further information about the project is available on the QUB Centre for Data Digitisation and Analysis website. Main Topics: The dataset contains population census data covering population, housing, religion, birthplaces, language, occupations, age structures, conjugal status and family structure. All the relevant background material is incorporated either in the documentation files or in the scanned images of the tables of contents, prefaces, and notes in the original source. The main population census tables are: Total population grouped by county districts and gender (1881-1971). Total number of buildings, classified as either inhabited buildings, uninhabited buildings, or buildings under construction grouped by county districts. Also includes the area and valuation of each county district (1881-1971). Total number of Roman Catholics, Church of Ireland members, Presbyterians, Methodists and others grouped by county districts and gender (1926-1971). Total number of Roman Catholics, Church of Ireland members and others grouped by counties, gender and age groups (1926-1971). Total numbers born in each county grouped by county of residence and gender (1901-1971) Republic of Ireland only. Total numbers born in each province grouped by county districts of residence and gender (1926-1936) Republic of Ireland only Total numbers born in each county district grouped by county of residence and gender (1926-1971) Northern Ireland only. Irish/English speakers and English only speakers grouped by county districts (1926-1971) Republic of Ireland only. Occupations grouped by counties and gender (1926-1971). Total number of persons in each age group grouped by county districts and gender (1901-1971). Total number of married, single and widowed people grouped by county districts, age groups and gender (1926-1971). Total number of families grouped by duration of marriage, husband's age at marriage, wife's age at marriage and number of children born (1946, 1961 and 1971) Republic of Ireland only. Total number of families grouped by counties, duration of marriage, wife's age at marriage and number of children born (1946, 1961 and 1971) Republic of Ireland only. Total number of families grouped by religious affiliation, duration of marriage, wife's age at marriage and number of children born (1946, 1961 and 1971) Republic of Ireland only. Total number of dependent children grouped by counties, number of children in family and parent's marital status, gender and age (1926 and 1946) Republic of Ireland only. Please note: this study does not include information on named individuals and would therefore not be useful for personal family history research.

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.

This dataset is comprised of selected county level counts for the province of Ontario, Canada derived from the published census reports of 1891, 1901, 1911, 1921, 1931, 1941, 1951 and 1961. It forms part of a larger project entitled 'The Orange Order in the 20th century: A study in social change'. This wider study explores the relative impact of techno-economic, cultural and institutional factors on Orange Order membership and political influence in twentieth century Scotland, Canada and Northern Ireland Please note: this study does not include information on named individuals and would therefore not be useful for personal family history research. Purposive selection/case studies Selected County level census counts Transcription of existing materials Compilation or synthesis of existing material