All counties in Pennsylvania
| County Name | Population | State | Rank |
|---|
| Philadelphia County | 1,526,006 | Pennsylvania | 1 |
| Allegheny County | 1,223,348 | Pennsylvania | 2 |
| Montgomery County | 799,874 | Pennsylvania | 3 |
| Bucks County | 625,249 | Pennsylvania | 4 |
| Delaware County | 558,979 | Pennsylvania | 5 |
| Lancaster County | 519,445 | Pennsylvania | 6 |
| Chester County | 498,886 | Pennsylvania | 7 |
| York County | 434,972 | Pennsylvania | 8 |
| Berks County | 411,442 | Pennsylvania | 9 |
| Westmoreland County | 365,169 | Pennsylvania | 10 |
| Lehigh County | 349,497 | Pennsylvania | 11 |
| Luzerne County | 320,918 | Pennsylvania | 12 |
| Northampton County | 297,735 | Pennsylvania | 13 |
| Erie County | 280,566 | Pennsylvania | 14 |
| Dauphin County | 268,100 | Pennsylvania | 15 |
| Cumberland County | 235,406 | Pennsylvania | 16 |
| Lackawanna County | 214,437 | Pennsylvania | 17 |
| Washington County | 207,820 | Pennsylvania | 18 |
| Butler County | 183,862 | Pennsylvania | 19 |
| Beaver County | 170,539 | Pennsylvania | 20 |
| Monroe County | 169,842 | Pennsylvania | 21 |
| Centre County | 153,990 | Pennsylvania | 22 |
| Franklin County | 149,618 | Pennsylvania | 23 |
| Schuylkill County | 148,289 | Pennsylvania | 24 |
| Cambria County | 143,679 | Pennsylvania | 25 |
| Fayette County | 136,606 | Pennsylvania | 26 |
| Lebanon County | 133,568 | Pennsylvania | 27 |
| Blair County | 127,089 | Pennsylvania | 28 |
| Mercer County | 116,638 | Pennsylvania | 29 |
| Lycoming County | 116,111 | Pennsylvania | 30 |
| Adams County | 101,407 | Pennsylvania | 31 |
| Northumberland County | 94,528 | Pennsylvania | 32 |
| Lawrence County | 91,108 | Pennsylvania | 33 |
| Indiana County | 88,880 | Pennsylvania | 34 |
| Crawford County | 88,765 | Pennsylvania | 35 |
| Clearfield County | 81,642 | Pennsylvania | 36 |
| Somerset County | 77,742 | Pennsylvania | 37 |
| Armstrong County | 68,941 | Pennsylvania | 38 |
| Columbia County | 67,295 | Pennsylvania | 39 |
| Carbon County | 65,249 | Pennsylvania | 40 |
| Bradford County | 62,622 | Pennsylvania | 41 |
| Pike County | 57,369 | Pennsylvania | 42 |
| Venango County | 54,984 | Pennsylvania | 43 |
| Wayne County | 52,822 | Pennsylvania | 44 |
| Bedford County | 49,762 | Pennsylvania | 45 |
| Mifflin County | 46,682 | Pennsylvania | 46 |
| Perry County | 45,969 | Pennsylvania | 47 |
| Huntingdon County | 45,913 | Pennsylvania | 48 |
| Jefferson County | 45,200 | Pennsylvania | 49 |
| Union County | 44,947 | Pennsylvania | 50 |
| Mckean County | 43,450 | Pennsylvania | 51 |
| Susquehanna County | 43,356 | Pennsylvania | 52 |
| Tioga County | 41,981 | Pennsylvania | 53 |
| Warren County | 41,815 | Pennsylvania | 54 |
| Clarion County | 39,988 | Pennsylvania | 55 |
| Snyder County | 39,702 | Pennsylvania | 56 |
| Clinton County | 39,238 | Pennsylvania | 57 |
| Greene County | 38,686 | Pennsylvania | 58 |
| Elk County | 31,946 | Pennsylvania | 59 |
| Wyoming County | 28,276 | Pennsylvania | 60 |
| Juniata County | 24,636 | Pennsylvania | 61 |
| Montour County | 18,267 | Pennsylvania | 62 |
| Potter County | 17,457 | Pennsylvania | 63 |
| Fulton County | 14,845 | Pennsylvania | 64 |
| Forest County | 7,716 | Pennsylvania | 65 |
| Sullivan County | 6,428 | Pennsylvania | 66 |
| Cameron County | 5,085 | Pennsylvania | 67 |