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.

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.

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.

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.