Ranking of Pennsylvania Counties By Population with Irish Ancestry in 2021

Updated on April 16, 2025.

Based on the US Census ACS-5Yrs estimates, in 2021, there were 1.97M people in Pennsylvania with Irish ancestry. Among all Pennsylvania counties, Allegheny County had the highest population with Irish ancestry (210.56K), followed by Montgomery County (169.40K), and Philadelphia County (158.21K).

The chart and table below shows the top 10 counties with high number of people with Irish ancestry.

You can see similar information for other states and for other ancestry groups in Pennsylvania.

Data Source: US Census Bureau.
Ranking of Pennsylvania Counties By Population with Irish Ancestry in 2021
Allegheny County
Montgomery County
Philadelphia County
Bucks County
Delaware County
Chester County
Westmoreland County
Luzerne County
Lancaster County
York County
Ranking of Pennsylvania Counties By Population with Irish Ancestry in 2021
0 of 0
Rank County Population
1 Allegheny County 210555
2 Montgomery County 169398
3 Philadelphia County 158209
4 Bucks County 147317
5 Delaware County 134295
6 Chester County 112331
7 Westmoreland County 60160
8 Luzerne County 56601
9 Lancaster County 56452
10 York County 54285
11 Lackawanna County 53884
12 Berks County 42232
13 Northampton County 40348
14 Erie County 40107
15 Lehigh County 38491
16 Butler County 37692
17 Cumberland County 35263
18 Washington County 34941
19 Dauphin County 28277
20 Beaver County 27454
21 Schuylkill County 25194
22 Monroe County 23221
23 Cambria County 23128
24 Blair County 21394
25 Fayette County 21179
26 Centre County 19885
27 Mercer County 17551
28 Franklin County 16186
29 Lycoming County 15647
30 Lawrence County 15257
31 Lebanon County 13734
32 Pike County 13309
33 Crawford County 13095
34 Adams County 12561
35 Indiana County 11557
36 Armstrong County 10914
37 Carbon County 9668
38 Northumberland County 9428
39 Wayne County 9417
40 Clearfield County 9082
41 Bradford County 8963
42 Venango County 8306
43 Somerset County 7903
44 Susquehanna County 7902
45 Columbia County 6652
46 Huntingdon County 6141
47 McKean County 6020
48 Mifflin County 5898
49 Clarion County 5586
50 Warren County 5503
51 Greene County 5243
52 Tioga County 5231
53 Bedford County 4850
54 Jefferson County 4832
55 Perry County 4701
56 Wyoming County 4300
57 Clinton County 4295
58 Elk County 4077
59 Union County 3526
60 Snyder County 3146
61 Potter County 2092
62 Juniata County 1958
63 Montour County 1878
64 Fulton County 1565
65 Sullivan County 1094
66 Forest County 720
67 Cameron County 434