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.

In 1821, the population of the island of Ireland 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 Act of Union in 1800. 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. If applying modern-day borders, the population of Northern Ireland was not growing as fast as the population of the Republic of Ireland before 1841, however it was not as severely affected by the famine, which was hardest felt in the east and south. 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 overall population of Ireland has never exceeded it's pre-famine levels. Decline continues through partition 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. Although there was much conflict in Ireland in 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 overall population began growing again in the second half of the 1900s. Recovery The population of the Republic of Ireland was at it's lowest in 1961, with 2.8 million people, which is almost four million fewer people than before the famine. Since then it has grown consistently, reaching 4.6 million in 2011 and expected to reach 5 million people by 2020. In Northern Ireland, the population began growing again from the beginning of the 1900s, but growth has been very slow. The only time it fell was in the 1970s, at the peak of The Troubles, where high unemployment and violence contributed to a lower birth rate and an increase in emigration. From the 1980s onwards, living standards improved and the population began growing again, reaching 1.8 million people in 2011.

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.

Between 1821 and 1921, the entire island of Ireland was a part of the United Kingdom of Great Britain and Ireland, after both islands were united by the Act of Union in 1800. This graph shows only the population of the six counties of Ireland that would go on to become Northern Ireland. The population was just under 1.4 million in 1821 and grew to 1.7 million in the next twenty years.

Between 1845 and 1849 the Great Famine devastated the overall population of Ireland, causing the deaths of approximately one million people, and causing a further million to emigrate. Although the famine affected the population of the west and south of Ireland much more severely than the north, the population of the six counties still fell by over 200,000 people between 1841 and 1851. The population then continued to fall, reaching it's lowest point in the 1890s where it was 1.2 million. The Northern Irish population then grows slowly until the mid to late 1900s, during which time the state of Northern Ireland was founded in 1921. The population the reaches over 1.54 million in the 1960s, before it falls again in the 1970s. This drop in population coincides with the outbreak and the most violent decade of the Troubles in Northern Ireland, which was a conflict that dominated Northern Irish daily life for decades. However, from 1981 onwards the population grows by 70,000 to 12,000 every ten years, surpassing it's pre-famine level in the 1990s.

From 1821 until 2011, the male and female populations of the 26 counties of the modern-day Republic of Ireland grew at a relatively similar rate, however some fluctuations did occur. During this time, the entire island of Ireland was a part of the United Kingdom of Great Britain and Ireland, after both islands were united by the Acts of Union in 1800. This graph shows the populations of the 26 counties that would later form the Republic of Ireland in 1921, and does not include the six counties that became known as Northern Ireland.

As we can see, both populations follow a relatively similar trend throughout their respective histories. In the first three entries, women outnumber men by 70,000 to 120,000, although these figures do not include military personnel which would narrow this margin. Both populations fall at a similar rate during and after the famine, however the male population does fall slightly faster, possibly due to an increased rate of emigration among males. Another point where both populations differ is in the early twentieth century, where the female population declines in a relatively smooth curve, although the male populations peak in the census data before and after both world wars. From 1956 onwards both populations follow a very similar trend, and grow at the same rate. The difference in population sizes never exceeds 30,000 people, until the final entry in 2011 where the population of men is 2.27 million and the population of women is 2.31 million.

Historical chart and dataset showing Ireland hunger statistics by year from 2001 to 2022.

Cholera is one of the foremost water-borne diseases of citizens in developing countries without adequate access to clean water or sanitation facilities. Every year, 3 to 5 million people worldwide are infected by cholera, of which more than 100,000 die. Cholera is a re-emerging disease whose spread remains difficult to predict. One way to improve our ability to predict cholera epidemics is to learn from the dynamics of past epidemics. Studying historical cholera epidemics improves our understanding of the natural history of cholera before there were effective public health interventions or public understanding of transmission. Recent examples of studies that revisited cholera epidemics include Bingham and colleagues who studied the role of the water supply in the London outbreak of 1849, and Kuo and colleagues (5) who identified the changing geographical patterns of cholera in Fukushima from 1882 and 1895. Here, the 1848 – 1850 cholera epidemic in Ireland is investigated. This epidemic was part of the second cholera pandemic, during which more than 45,698 cases and 19,325 deaths were reported to Ireland’s Central Board of Health. It began during the Irish famine (1845 – 1852), when, between the censuses of 1841 to 1851, the population of Ireland dropped by 1,622,739 people through starvation, disease, and emigration, to a total population of 6,552,385. Epidemiology of the cholera epidemic of 1848 – 1850 in Ireland The second cholera pandemic began in 1829 in India, and first arrived in Ireland in Dublin in March, 1832. This first arrival of cholera in Ireland spread to the principal towns, but subsided quickly. The famine of Ireland began with the potato blight in 1845, which led to migration of Irish people to cities and workhouses in search of work and food. The first reported case of this epidemic was a man just arrived from Edinburgh and took place on December 4, 1848 in a workhouse in Belfast.

At the beginning of the 1840s, life expectancy from birth in Ireland was just over 38 years. However, this figure would see a dramatic decline with the beginning of the Great Famine in 1845, and dropped below 21 years in the second half of the decade (in 1849 alone, life expectancy fell to just 14 years). The famine came as a result of a Europe-wide potato blight, which had a disproportionally devastating impact on the Irish population due to the dependency on potatoes (particularly in the south and east), and the prevalence of a single variety of potato on the island that allowed the blight to spread faster than in other areas of Europe. Additionally, authorities forcefully redirected much of the country's surplus grain to the British mainland, which exacerbated the situation. Within five years, mass starvation would contribute to the deaths of over one million people on the island, while a further one million would emigrate; this also created a legacy of emigration from Ireland, which saw the population continue to fall until the mid-1900s, and the total population of the island is still well below its pre-famine level of 8.5 million people.

Following the end of the Great Famine, life expectancy would begin to gradually increase in Ireland, as post-famine reforms would see improvements in the living standards of the country’s peasantry, most notably the Land Wars, a largely successful series of strikes, boycotts and protests aimed at reform of the country's agricultural land distribution, which began in the 1870s and lasted into the 20th century. As these reforms were implemented, life expectancy in Ireland would rise to more than fifty years by the turn of the century. While this rise would slow somewhat in the 1910s, due to the large number of Irish soldiers who fought in the First World War and the Spanish Flu pandemic, as well as the period of civil unrest leading up to the island's partition in 1921, life expectancy in Ireland would rise greatly in the 20th century. In the second half of the 20th century, Ireland's healthcare system and living standards developed similarly to the rest of Western Europe, and today, it is often ranks among the top countries globally in terms of human development, GDP and quality of healthcare. With these developments, the increase in life expectancy from birth in Ireland was relatively constant in the first century of independence, and in 2020 is estimated to be 82 years.

The dataset provides detailed, standardised records of prisoners, including demographic, physical, and judicial information such as age, height, offence, birthplace, residence, occupation, religion, and literacy.

The dataset offers a comprehensive resource for studying social, economic, demographic, and anthropometric history of Ireland under British rule. Prisoners' names are anonymised to comply with data-sharing agreements. Recidivists are only included in this dataset the first time they are entered into the prison register.

Year of conviction ranges from 1858 to 1910, and the year of birth is from 1840 to 1859. The average age of the prison population is 34, and ages range from 16 to 70.

Data are described in more detail in E. McLaughlin, C. L. Colvin and M. Blum, 'Anthropometric History: Revisiting What’s in it for Ireland', Irish Economic and Social History (2021).

Occupations are classified into five categories using the Armstrong scale: W. A. Armstrong, ‘The use of information about occupation, part I: a basis for social stratification’, in E. A. Wrigley (ed.), Nineteenth-century society: essays in the use of quantitative methods for the study of social data (Cambridge, 1972).

Famine-era mortality is appended to this dataset, denoting excess mortality in a prisoner's county of birth during the Great Irish Famine. This is calculated by comparing the 1841 and 1851 censuses, as calculated by Joel Mokyr, Why Ireland starved (2nd ed., London, 1985).

This project presents a hand-collected dataset of over 18,620 individuals incarcerated in Kilmainham Gaol (1837–1910) or Clonmel Gaol (1848–1929), derived from surviving General Prison Registers for these two prisons held at the National Archives of Ireland in Dublin (NAI/Pris1/3 and NAI/Pris1/33).

Between 1820 and 1957, over 4.6 million people emigrated from the island of Ireland to the United States. The period with the highest levels of migration came between 1845 and 1855 , as the Great Famine devastated Ireland's population, causing the deaths of roughly one million people and leading to the migration of one million more, most of which was to the United States. The period with the lowest levels of migration came in the 1930s and 40s, as the Great Depression and Second World War created an environment where migration to the US was difficult or impractical.

Prior to 1921, the six counties that make up modern-day Northern Ireland were a part of the United Kingdom of Great Britain and Ireland, and the separate state of Northern Ireland did not exist until after the partition of Ireland in 1921. From 1821 until 1841, both the male and female populations grew by 130,000 each, until the Great Famine of 1845 to 1849 caused a sharp decline in the population in the 1840s. This decline continued until 1891, and the male population of the six counties fell at a slightly higher rate than the female population. The number of men fell by 310,000 between 1841 and 1891, and the number of women fell by 300,000. From 1891 to 1937 growth remains quite low, particularly among women, and then from 1937 the growth rate increases again. There is one more decade where the population dropped, which coincides with the most violent period of the Northern Irish Troubles. This was in the 1970s, where the number of men and women fell by approximately 30,000 each.

In the nineteenth and twentieth centuries, the majority of documented migration to the United States of American came from European countries. Between 1820 and 1957, of the approximate 41 million migrants to the US, over 34 million of these came from Europe. The most commonly documented countries of origin during this time were Germany (6.6 million), Italy (4.9 million), Ireland (4.6 million), Great Britain (4.5 million), and Russia (3.4 million). The first wave of mass migration came in the 1850s, as the Great famine crippled Ireland's population, and many in rural areas of mainland Europe struggled to adapt to industrialization, and economic opportunities attracted many in the 1870s, following the American Civil War. The 1880s saw another wave, as steam powered ships and lower fares made trans-Atlantic journeys much more affordable. The first wave of mass migration from Eastern and Southern Europe also arrived at this time, as industrialization and agricultural advancements led to high unemployment in these regions.

The majority of migrants to the United States settled in major urban centers, which allowed the expansion of industry, leading to the United States' emergence as one of the leading global economies at the turn of the twentieth century. The largest wave of migration to the United states during this period came in the first fifteen years of the 1900s. The influx of migrants from Northern and Western Europe had now been replaced by an influx from Eastern and Southern Europe (although migration from the British Isles was still quite high during this time). European migration fell to it's lowest levels in eighty years during the First World War, before fluctuating again in the interwar period, due to the Great Depression. As the twentieth century progressed, the continent with the highest levels of migration to the US gradually changed from Europe to Latin America, as economic opportunities in Western Europe improved, and the US' relationship with the Soviet Union and other Eastern, communist states became complicated.