| class="wikitable sortable"
! Rank
! County
! Area (km2)
! Density (/ km2)
! Traditional province |
| align=right | 1
| Cork
| align=right | {{nts|7,508}} [{{cite web |url= https://www.gov.ie/en/publication/3f109-report-of-the-expert-advisory-group-on-local-government-arrangements-in-cork/ |publisher= Department of Housing, Local Government and Heritage |website= gov.ie |title= Report of the Expert Advisory Group on Local Government Arrangements in Cork |access-date=28 October 2023 |archive-url= |archive-date= |quote= Area (Cork County: 7,467.91 km2 / Cork City: 39.61 km2}}]
| align=right | 77.8
| Munster |
| align=right | 2
| Galway
| align=right | {{nts|6,151}} [{{cite web | title = County Profiles – Galway | url = https://westerndevelopment.ie/policy/our-region/galway-county-analysis/ | publisher = Western Development Commission | access-date = 2 June 2021 | archive-date = 2 June 2021 | archive-url = https://web.archive.org/web/20210602213650/https://westerndevelopment.ie/policy/our-region/galway-county-analysis/ | url-status = live }}]
| align=right | 45.1
| Connacht |
| align=right | 3
| Mayo
| align=right | {{nts|5,588}} [{{cite web | title = County Profiles – Mayo | url = https://westerndevelopment.ie/policy/our-region/mayo-county-analysis/ | publisher = Western Development Commission | access-date = 2 June 2021 | archive-date = 2 June 2021 | archive-url = https://web.archive.org/web/20210602225539/https://westerndevelopment.ie/policy/our-region/mayo-county-analysis/ | url-status = live }}]
| align=right | 24.7
| Connacht |
| align=right | 4
| Donegal
| align=right | {{nts|4,860}} [{{cite web |title=County Profiles – Donegal |url=https://westerndevelopment.ie/policy/our-region/donegal-county-analysis/ |publisher=Western Development Commission |access-date=2 June 2021 |archive-date=2 June 2021 |archive-url=https://web.archive.org/web/20210602221024/https://westerndevelopment.ie/policy/our-region/donegal-county-analysis/ |url-status=live}}]
| align=right | 34.4
| Ulster |
| align=right | 5
| Kerry
| align=right | {{nts|4,807}} [[https://web.archive.org/web/20111114162834/http://www.cso.ie//studentscorner/statsfactskerry.htm] County Kerry]
| align=right | 32.5
| Munster |
| align=right | 6
| Tipperary
| align=right | {{nts|4,305}} [[https://web.archive.org/web/20111114162838/http://www.cso.ie//studentscorner/statsfactstipperary.htm] County Tipperary]
| align=right | 39.0
| Munster |
| align=right | 7
| Clare
| align=right | {{nts|3,450}} [[https://web.archive.org/web/20111114162829/http://www.cso.ie//studentscorner/statsfactsclare.htm] County Clare]
| align=right | 37.1
| Munster |
| align=right | 8
| Tyrone
| align=right | {{nts|3,266}} [{{cite book |author=Northern Ireland General Register Office |title=Census of Population 1971; Summary Tables |url=https://www.nisra.gov.uk/sites/nisra.gov.uk/files/publications/1971-census-summary-tables.pdf#page=21 |format=PDF |location=Belfast |publisher=HMSO |access-date=28 August 2019 |page=1 |chapter=Table 1: Area, Buildings for Habitation and Population, 1971 |date=1975}}]
| align=right | 57.6
| Ulster |
| align=right | 9
| Antrim
| align=right | {{nts|3,086}} [{{cite web |archive-url=https://web.archive.org/web/20150824021440/http://www.proni.gov.uk/index/local_history/areas_regions_and_land_divisions/main_administrative_land_divisions.htm |archive-date=24 August 2015 |url=http://www.proni.gov.uk/index/local_history/areas_regions_and_land_divisions/main_administrative_land_divisions.htm |publisher=Public Records Office of Northern Ireland |title=Areas, regions, and land divisions}}]
| align=right | 211.1
| Ulster |
| align=right | 10
| Limerick
| align=right | {{nts|2,756}} [[https://web.archive.org/web/20111114162836/http://www.cso.ie//studentscorner/statsfactslimerick.htm] County Limerick]
| align=right | 76.0
| Munster |
| align=right | 11
| Roscommon
| align=right | {{nts|2,548}} [[https://web.archive.org/web/20111114162824/http://www.cso.ie//studentscorner/statsfactsroscommon.htm] County Roscommon]
| align=right | 27.6
| Connacht |
| align=right | 12
| Down
| align=right | {{nts|2,489}}
| align=right | 222.3
| Ulster |
| align=right | 13
| Wexford
| align=right | {{nts|2,367}} [[https://web.archive.org/web/20111114162906/http://www.cso.ie//studentscorner/statsfactswexford.htm] County Wexford]
| align=right | 69.3
| Leinster |
| align=right | 14
| Meath
| align=right | {{nts|2,342}} [[https://web.archive.org/web/20111114162859/http://www.cso.ie//studentscorner/statsfactsmeath.htm] County Meath]
| align=right | 94.3
| Leinster |
| align=right | 15
| Londonderry
| align=right | {{nts|2,118}}
| align=right | 119.1
| Ulster |
| align=right | 16
| Kilkenny
| align=right | {{nts|2,073}} [[https://web.archive.org/web/20111114162850/http://www.cso.ie//studentscorner/statsfactskilkenny.htm] County Kilkenny]
| align=right | 50.2
| Leinster |
| align=right | 17
| Wicklow
| align=right | {{nts|2,027}} [[https://web.archive.org/web/20111114162908/http://www.cso.ie//studentscorner/statsfactswicklow.htm] County Wicklow]
| align=right | 76.9
| Leinster |
| align=right | 18
| Offaly
| align=right | {{nts|2,001}} [[https://web.archive.org/web/20111114162901/http://www.cso.ie//studentscorner/statsfactsoffaly.htm] County Offaly]
| align=right | 41.6
| Leinster |
| align=right | 19
| Cavan
| align=right | {{nts|1,932}} [[https://web.archive.org/web/20111114162910/http://www.cso.ie//studentscorner/statsfactscavan.htm] County Cavan]
| align=right | 42.3
| Ulster |
| align=right | 20
| Waterford
| align=right | {{nts|1,858}} [[https://web.archive.org/web/20111114162841/http://www.cso.ie//studentscorner/statsfactswaterford.htm] County Waterford]
| align=right | 68.6
| Munster |
| align=right | 21
| Westmeath
| align=right | {{nts|1,840}} [[https://web.archive.org/web/20111114162904/http://www.cso.ie//studentscorner/statsfactswestmeath.htm] County Westmeath]
| align=right | 52.3
| Leinster |
| align=right | 22
| Sligo
| align=right | {{nts|1,838}} [[https://web.archive.org/web/20111114162827/http://www.cso.ie//studentscorner/statsfactssligo.htm] County Sligo]
| align=right | 38.2
| Connacht |
| align=right | 23
| Laois
| align=right | {{nts|1,720}} [[https://web.archive.org/web/20111114162852/http://www.cso.ie//studentscorner/statsfactslaois.htm] County Laois]
| align=right | 53.4
| Leinster |
| align=right | 24
| Kildare
| align=right | {{nts|1,695}} [[https://web.archive.org/web/20111114162848/http://www.cso.ie//studentscorner/statsfactskildare.htm] County Kildare]
| align=right | 146.2
| Leinster |
| align=right | 25
| Fermanagh
| align=right | {{nts|1,691}} [[http://www.thefreedictionary.com/County+Fermanagh] County Fermanagh]
| align=right | 37.6
| Ulster |
| align=right | 26
| Leitrim
| align=right | {{nts|1,589}} [{{cite web | title = County Profiles – Leitrim | url = https://westerndevelopment.ie/policy/our-region/leitrim-county-analysis/ | publisher = Western Development Commission | access-date = 17 April 2024}}]
| align=right | 22.2
| Connacht |
| align=right | 27
| Armagh
| align=right | {{nts|1,327}}
| align=right | 146.5
| Ulster |
| align=right | 28
| Monaghan
| align=right | {{nts|1,295}} [[https://web.archive.org/web/20111114162915/http://www.cso.ie//studentscorner/statsfactsmonaghan.htm] County Monaghan]
| align=right | 50.4
| Ulster |
| align=right | 29
| Longford
| align=right | {{nts|1,091}} [[https://web.archive.org/web/20111114162854/http://www.cso.ie//studentscorner/statsfactslongford.htm] County Longford]
| align=right | 42.9
| Leinster |
| align=right | 30
| Dublin
| align=right | {{nts|922}} [[https://web.archive.org/web/20111114162845/http://www.cso.ie//studentscorner/statsfactsdublin.htm] County Dublin]
| align=right | 1,581.5
| Leinster |
| align=right | 31
| Carlow
| align=right | {{nts|897}} [[https://web.archive.org/web/20111114162843/http://www.cso.ie//studentscorner/statsfactscarlow.htm] County Carlow]
| align=right | 69.1
| Leinster |
| align=right | 32
| Louth
| align=right | {{nts|826}} [[https://web.archive.org/web/20111114162857/http://www.cso.ie//studentscorner/statsfactslouth.htm] County Louth]
| align=right | 169.1
| Leinster |
| align=right |
| Average
| align=right | {{nts|2,633}}
| align=right |
| align=right | |
| Total
| Ireland
| align=right | {{nts|84,421}}
| align=right | 83.5
| align=right | |