Irish Population in Pennsylvania by County : 2025 Ranking & Insights

According to U.S. Census estimates, the Irish population in Pennsylvania totals 1.9 million. Every county in the state reports a non-zero population, with Allegheny County leading at 208,310, followed by Montgomery County (164,048) and Philadelphia County (152,672). This demographic analysis ranks all counties in Pennsylvania by their Irish population, offering insights into regional distribution patterns and highlighting county-level concentrations across the state.

Top 5 counties with the largest Irish population in Pennsylvania

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  • 1
    Allegheny County
    Irish population in Allegheny County is 208,310
    16.79% of Allegheny County population is Irish
  • 2
    Montgomery County
    Irish population in Montgomery County is 164,048
    19.05% of Montgomery County population is Irish
  • 3
    Philadelphia County
    Irish population in Philadelphia County is 152,672
    9.65% of Philadelphia County population is Irish
  • 4
    Bucks County
    Irish population in Bucks County is 143,247
    22.17% of Bucks County population is Irish
  • 5
    Delaware County
    Irish population in Delaware County is 127,668
    22.16% of Delaware County population is Irish

Overview of Irish population in Pennsylvania

  • Population Count and Percentage: American Community Survey show Pennsylvania contains 1.9 million Irish residents (14.8% of 13.0 million total state population), positioning the state at the 95th percentile nationally among U.S. states for Irish population concentrations.
  • Comparison to State and National Averages: U.S. Census data records indicate Pennsylvania's Irish population of 14.8% exceeds the national average of 9.4% by a factor of 1.6.
  • Share of Total National Population: Official American Community Survey records show Pennsylvania hosts 1.9 million Irish residents, representing 6.2% of the nation's total Irish population of 31.2 million, establishing the state as a significant demographic concentration center within national boundaries.
  • Population Density per Square Mile: U.S. Census Bureau's American Community Survey data indicates Pennsylvania's density of 43 Irish Americans per square mile exceeds the national average of 8.8 per square mile by more than quadruple, establishing the state as a significant concentration center for Irish demographic communities.
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67 Counties in Pennsylvania Ranked by Irish Population

View Methodology
American Community Survey data [1] show Irish populations across every county in Pennsylvania, with demographic distributions ranging from the highest population in Allegheny County to the lowest in $rank_n_geo_name. The table below provides broader statistics, including total population figures, density measures, and demographic distributions based on current ACS data for all counties included in this analysis*.
counties in Pennsylvania ranked by Irish population count
Rank by Irish Population
County
Irish Population
% of Total County Population
% of Total Pennsylvania Irish Population
5 Year Rank Trend
1 Allegheny County 208,310 16.79% 10.82%
2 Montgomery County 164,048 19.05% 8.52%
3 Philadelphia County 152,672 9.65% 7.93%
4 Bucks County 143,247 22.17% 7.44%
5 Delaware County 127,668 22.16% 6.63%
6 Chester County 112,516 20.80% 5.84%
7 Westmoreland County 59,104 16.73% 3.07%
8 56,787 10.23% 2.95%
9 54,731 11.92% 2.84%
10 53,302 16.35% 2.77%
11 50,100 23.21% 2.60%
12 42,040 9.78% 2.18%
13 38,097 19.45% 1.98%
14 38,070 12.05% 1.98%
15 37,813 10.07% 1.96%
16 35,627 13.22% 1.85%
17 34,208 12.94% 1.78%
18 33,850 16.14% 1.76%
19 30,079 10.46% 1.56%
20 27,778 16.63% 1.44%
21 25,393 17.73% 1.32%
22 23,168 13.81% 1.20%
23 22,142 16.73% 1.15%
24 22,111 18.15% 1.15%
25 21,265 13.46% 1.10%
26 19,429 15.30% 1.01%
27 16,289 14.83% 0.85%
28 15,752 10.06% 0.82%
29 15,264 13.44% 0.79%
30 14,942 17.49% 0.78%
31 13,965 9.73% 0.73%
32 13,682 13.01% 0.71%
33 12,699 15.27% 0.66%
34 11,432 19.15% 0.59%
35 10,839 13.03% 0.56%
36 10,508 16.15% 0.55%
37 10,014 11.01% 0.52%
38 9,450 14.50% 0.49%
39 9,371 18.31% 0.49%
40 9,337 11.83% 0.49%
41 8,020 16.01% 0.42%
42 7,983 13.31% 0.41%
43 7,723 20.14% 0.40%
44 7,286 9.95% 0.38%
45 6,144 9.44% 0.32%
46 5,910 12.83% 0.31%
47 5,909 13.48% 0.31%
48 5,701 14.20% 0.30%
49 5,441 14.25% 0.28%
50 5,358 14.37% 0.28%
51 5,275 11.47% 0.27%
52 5,054 11.46% 0.26%
53 4,995 14.16% 0.26%
54 4,982 10.49% 0.26%
55 4,628 11.27% 0.24%
56 4,433 11.76% 0.23%
57 3,924 15.05% 0.20%
58 3,858 12.57% 0.20%
59 3,201 8.06% 0.17%
60 2,941 6.91% 0.15%
61 1,951 8.33% 0.10%
62 1,940 10.73% 0.10%
63 1,875 11.52% 0.10%
64 1,356 9.32% 0.07%
65 893 15.27% 0.05%
66 752 11.08% 0.04%
67 589 13.16% 0.03%
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Methodology

This ranking list is based on data from the American Community Survey (ACS) 5-Year Estimates, conducted by the U.S. Census Bureau. The ACS is one of the most reliable sources for understanding population trends across different locations, and it provides estimates for various racial and ethnic groups at city, county, state and all geography levels down to the Census block group.
This list ranks county in Pennsylvania by their Irish population, using the most recent ACS data available.

How the Census defines Irish population

The U.S. Census Bureau allows people to self-identify their ancestry, meaning individuals can write upto ancestries when responding to the survey. In this ranking, we include everyone who identifies as having Irish ancestry, whether alone or in combination with another ancestry.
Here are a few important things to know about how ancestry is reported:
  • Some people identify as Irish alone, while others identify as Irish along with another race (such as Irish and German).
  • We’ve used the “Irish alone or in any combination” category unless noted otherwise, which gives a broader picture of the Irish population in each area.

How We Ranked the Data

This ranking is based on the total number of people who identified as Irish alone or in combination in county. To provide additional context, we’ve also included two key percentages:
  1. % of Total County Population – This shows what percentage of the total state population identifies as Irish .
  2. % of Total Pennsylvania Irish Population – This tells us how much of the entire U.S. Irish population lives in that state.
To keep things simple, all population numbers have been rounded to the nearest whole number, and percentages are rounded to one decimal place. Because of rounding, some percentages may not add up to exactly 100%.

Things to Keep in Mind

Like all survey-based data, ACS estimates come with some limitations. Here are a few things to be aware of:
  • In places with very small Irish populations, the numbers may not be reported at all due to privacy protections or sampling variability in the survey.
  • Since the ACS is based on a sample, the numbers are estimates, not exact counts. That means they may slightly differ from other sources like the decennial U.S. Census.
  • County that don’t have any reported Irish population are not included in the ranking but are listed separately below for reference.
This ranking is meant to provide a clear, data-driven look at where Irish populations are most concentrated while keeping the numbers easy to understand.

Sources

  1. 2019-2023 5-Year Estimates.
  2. 2023.