County Cork dominates as Ireland’s largest county by area, spanning 7,508 km², while Dublin leads in population with 1,450,701 residents. Galway ranks second by land size at 6,151 km² while remaining fifth in headcount, illustrating Ireland’s geographic mismatch between size and population.

4 related posts

Largest by area: County Cork (7,508 km²) ·
Second largest by area: County Galway (6,151 km²) ·
Largest by population: County Dublin (1,450,701) ·
Counties in Republic of Ireland: 26 ·
Counties in Northern Ireland: 6

Quick snapshot

1Confirmed facts
2What’s unclear
  • Whether recent boundary adjustments affect rankings for smaller counties
  • Projected population shifts for 2030 not publicly confirmed
3Timeline signal
  • Cork’s population grew 9.5% from 2002 to 2006 (World Atlas)
  • Ireland’s population rose 3.8% between 2011–2016 (World Atlas)
4What’s next
  • Dublin’s dominance may intensify as urban concentration grows
  • Rural counties like Mayo and Donegal face continued density decline
Metric Value
Total counties 32
Largest area County Cork, 7,508 km²
Smallest area Louth
Largest population County Dublin, 1,450,701

What are the top 5 largest counties in Ireland?

When ranking by land area, the top five counties form a corridor across the western seaboard and the south-west, with Mayo breaking the pattern as the sole Connacht representative in the top three. This geography reflects Ireland’s glacial past—counties shaped by ancient ice sheets tend toward larger, irregular footprints.

By land area

County Cork dominates the ranking at 7,508 km², followed by Galway (6,151 km²), Mayo (5,588 km²), Donegal (4,860 km²), and Kerry (4,807 km²). Mayo’s inclusion at third place surprises many readers who associate the county with rural decline. Research from World Atlas (geographic reference source) notes that these five counties together account for nearly 40% of the island’s total landmass.

By population

Population rankings tell a different story. Dublin leads with 1,450,701 residents in 2022—representing 28% of the Republic’s entire population—followed by Cork at 542,196, according to UK Population Data (census aggregation service). Fingal (296,214), South Dublin (278,749), and Galway (258,058) round out the top five.

The paradox

Mayo spans 5,588 km²—larger than all of Northern Ireland’s six counties combined—yet holds fewer than 135,000 residents. Galway, by contrast, manages 258,058 people across its 6,151 km², a density advantage that reflects its coastal cities.

What is the largest county in Ireland by area?

County Cork claims the top spot by area, occupying 7,508 km² along Ireland’s southern coast. Wikipedia (primary geographic reference) places it ahead of Galway by over 1,350 km²—a difference larger than the entire county of Louth. Cork is also the southernmost and most extensive county on the island.

County Cork details

Cork sits in the province of Munster, surrounded by Waterford, Tipperary, Limerick, and Kerry. The county takes its name from the city of Cork, the third most populous city in Ireland. With a population density of just 77.8 per km², the county remains largely rural despite its urban namesake.

Comparison to others

To put Cork’s scale in perspective: it is larger than six of Ireland’s counties combined, or roughly equal to the combined area of the five smallest counties. Kiddle (educational reference) notes that Cork’s area exceeds 2,800 square miles.

“County Cork is the southernmost and most extensive county in Ireland, occupying an area of approximately 2,900 sq mi.”

— World Atlas, geographic reference source

What is the largest county in Ireland by population?

Dublin is the largest county in Ireland by population with 1,450,701 residents in 2022, according to UK Population Data. However, when considering the Republic of Ireland alone, County Cork ranks second by population—a unique dual dominance that no other county matches.

Top population rankings

The top five most populous counties are Dublin (1,450,701), Cork (542,196), Fingal (296,214), South Dublin (278,749), and Galway (258,058). Ireland Wiki (community data aggregator) records Dublin’s growth at 7.02% since the previous census, outpacing most rural counties.

Urban influences

Four of the top five most populous counties are either Dublin itself or parts of Greater Dublin—a testament to economic concentration in the capital. Galway breaks the pattern as the only non-Dublin county in the top five, reflecting its role as a regional hub for the west.

Why this matters

For policymakers, Cork’s dual status as both largest by area and second by population creates distinct pressures: rural infrastructure demands across vast distances alongside urban growth management in Cork city.

“It is Ireland’s largest inland county and shares a border with eight counties, more than any other.”

— Wikipedia, reference source

What is the second largest county in Ireland?

County Galway ranks second by area at 6,151 km², according to Wikipedia. Unlike Cork, which leads both area and population categories, Galway leads in land size while only ranking fifth in population—a gap that highlights the county’s mountainous, sparsely populated interior.

By area: Galway

Galway occupies 6,151 km² on Ireland’s west coast, sharing a border with Mayo, Roscommon, Offaly, and Clare. The World Atlas (geographic reference source) describes Galway as a county shaped by the Connemara mountains and the limestone karst of the Burren, landscapes that limit agricultural density.

By population differences

Galway’s 258,058 residents concentrate heavily in Galway city, creating a population density of 45.1 per km²—roughly double Mayo’s 24.7 per km². Kiddle (educational reference) records this contrast, noting the county’s urban-rural divide.

What is the largest county in Ulster?

Donegal is the largest county in Ulster by area at 4,860 km², according to Wikipedia. However, by population, Antrim leads Northern Ireland’s six counties with 618,108 residents, followed by Down at 531,665, per UK Population Data.

Ulster counties ranked

Of Ireland’s 32 counties, six sit in Northern Ireland: Antrim, Armagh, Down, Fermanagh, Londonderry, and Tyrone. Wikipedia (primary geographic reference) notes that all six fall below the Republic’s top ten by area, with Donegal at 4,860 km² serving as the largest Ulster representative.

Area vs population

Antrim covers approximately 3,132 km² yet holds 618,108 residents—the highest density among Northern Ireland counties. Ireland Wiki (community data aggregator) records Down’s population growth at 7.84% since the previous census, the highest growth rate among Northern Ireland’s top two counties.

Ireland’s largest counties: area vs population comparison

Nine counties, two ranking systems: one pattern emerges clearly. Urban concentration rewards small land areas, while rural counties sprawl across vast territories with relatively few residents.

County Area (km²) Population (2022) Density (per km²) Province
Cork 7,508 542,196 77.8 Munster
Galway 6,151 258,058 45.1 Connacht
Mayo 5,588 134,609 24.7 Connacht
Donegal 4,860 166,839 34.4 Ulster
Kerry 4,807 156,458 32.5 Munster
Dublin 1,180 1,450,701 1,380.8 Leinster
Antrim 3,132 618,108 197.2 Ulster (NI)
Down 2,448 531,665 216.9 Ulster (NI)
Tipperary 4,305 167,895 39.0 Munster

The implication: Cork’s dominance by area coexists with moderate population density, while Dublin’s tiny footprint absorbs over 1.4 million people. Tipperary, often overlooked in these rankings, deserves note as the largest inland county, sharing borders with eight counties—more than any other.

Upsides

  • Cork offers both scale and population—rare dual leadership among all 32 counties
  • Galway and Mayo provide extensive rural land for agriculture, tourism, and renewable energy projects
  • Northern Ireland counties (Antrim, Down) show strong population growth, suggesting economic vitality

Downsides

  • Mayo and Donegal face chronic underpopulation—schools, hospitals, and services become unsustainable
  • Dublin’s concentration creates infrastructure strain and housing pressure
  • Western seaboard counties (Mayo, Donegal) lack urban cores to retain young residents

Related reading: Counties of Ireland · Places to Visit in Dublin

Additional sources

en.wikipedia.org, academickids.com, gammalabs.ie, ireland.com, datacommons.org, math.answers.com

Cork’s lead in both land area and population aligns with area and population rankings, which examines the same metrics across all counties.

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Frequently asked questions

What is the smallest county in Ireland?

County Louth is the smallest county by area, occupying approximately 826 km² in Leinster. By contrast, Louth is more densely populated than several larger counties, with over 226,000 residents.

How many counties are in the Republic of Ireland?

Of Ireland’s 32 counties, 26 are in the Republic of Ireland and 6 are in Northern Ireland, per Wikipedia (primary geographic reference).

What provinces include the largest counties?

Munster (Cork, Kerry) and Connacht (Galway, Mayo) dominate the top five by area, while Leinster hosts Dublin and its satellite counties by population.

Is County Cork largest by both area and population?

Cork is the largest county by area (7,508 km²) and second by population (542,196) in the Republic of Ireland. Dublin leads by population nationally.

What is the area of County Galway?

County Galway covers 6,151 km², making it the second largest county in Ireland by area, according to Wikipedia.

Which county has the highest population density?

Dublin leads by population density at approximately 1,380.8 per km², far exceeding any other county. Antrim follows among Northern Ireland counties at 197.2 per km².

Are Northern Ireland counties included in rankings?

Yes, the island of Ireland comprises 32 counties total—26 in the Republic and 6 in Northern Ireland. Area rankings include all 32; population rankings are typically shown separately by jurisdiction.

What is the largest county in Ulster?

Donegal is the largest county in Ulster by area (4,860 km²), while Antrim is the largest by population (618,108 residents) among Northern Ireland’s six counties.

For travelers planning routes, Cork’s size means scenic drives from Kinsale to Kenmare can consume an entire day. For policymakers, the density gap between Cork city and Mayo’s interior presents infrastructure challenges that no other county matches in complexity.

Bottom line: County Cork holds Ireland’s largest-county title by area, but Dublin’s density dominance means that when geography meets demographics, two very different stories emerge. Tourists exploring the west should prioritize Galway and Mayo for landscape; those interested in urban Ireland should focus on Dublin and Cork city.