This article gives information about the counties of Ireland (and Northern Ireland), including a table listing the population of Ireland by county.
How many counties are there in Ireland?
There are 26 counties in the Republic of Ireland (Éire) and a further 6 in Northern Ireland.
These traditional counties are are spread across the four traditional provinces of Ireland – Ulster, Connacht, Leinster and Munster.
You can see a full list later in this article, sorted by population.
Largest County in Ireland
County Dublin is the largest county in Ireland, with a population of 1,450,701 in 2022. That’s 28% of the population of the entire Republic of Ireland.
Antrim is the largest county in Northern Ireland, with a population of 618,108, followed by County Down (population 531,665).
Cork is the second largest county in the Republic of Ireland, the third largest on the island of Ireland.
Smallest county in Ireland
Leitrim in Connacht is the smallest county in Ireland by population. In 2022 it had a population of 35,087. Leitrim is preceded by Longford in Leinster, with a population of 46,634. Longford is the county with the fastest population growth in Ireland – it’s population grew by 14% between the 2016 and 2022 censuses.
Fermanagh is the smallest county in Northern Ireland, home to 61,170 people at the time of the last census in 2011. By the time the Northern Ireland census results are out, it may be that Fermanagh is has a bigger population than Carlow, which is the next smallest county in the Republic of Ireland.
Largest Province in Ireland
Historically Ireland has been divided into four provinces – Connacht, Leinster, Munster and Ulster . Each of the counties falls within one of these four provinces.
Leinster is the largest province in both Ireland and the Republic of Ireland.
Ireland counties by population
The table below lists the population of all of the counties of Ireland and Northern Ireland.
Our Irish counties list shows that County Dublin is the most populated county in Ireland, Leitrim is the least populated county in Ireland.
What county is Dublin in?
The city of Dublin is in County Dublin.
Since 1994, the county of Dublin has been split into four smaller local government areas – Dublin City, Dún Laoghaire–Rathdown, Fingal and South Dublin.
What county is Belfast in?
Belfast is in County Antrim in Northern Ireland and also the province of Ulster.
As noted above, Antrim is the largest county in Northern Ireland and the second largest on the island of Ireland. Belfast makes up just over half the population of Antrim.