The largest county in Pennsylvania
There are two right answers. By land area it is Lycoming County; by population it is Philadelphia County. Which one you want depends on what you meant by largest.
Sources: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026; US Census Bureau, Gazetteer Files, 2025 Gazetteer Files, released 10 September 2025. Retrieved 30 August 2026.
By land area
| Rank | Name | Land area | Population |
|---|---|---|---|
| 1 | Lycoming County | 1,229 sq mi | 112,587 |
| 2 | Bradford County | 1,147 sq mi | 59,600 |
| 3 | Clearfield County | 1,145 sq mi | 78,100 |
| 4 | Tioga County | 1,134 sq mi | 40,502 |
| 5 | Centre County | 1,107 sq mi | 157,393 |
| 6 | Potter County | 1,081 sq mi | 15,897 |
| 7 | Somerset County | 1,075 sq mi | 72,004 |
| 8 | Westmoreland County | 1,028 sq mi | 349,324 |
| 9 | Crawford County | 1,012 sq mi | 81,792 |
| 10 | Bedford County | 1,012 sq mi | 47,480 |
By population
| Rank | Name | Population | Density |
|---|---|---|---|
| 1 | Philadelphia County | 1,574,281 | 11,720 per sq mi |
| 2 | Allegheny County | 1,225,035 | 1,678 per sq mi |
| 3 | Montgomery County | 877,643 | 1,817 per sq mi |
| 4 | Bucks County | 647,828 | 1,072 per sq mi |
| 5 | Delaware County | 580,937 | 3,161 per sq mi |
| 6 | Lancaster County | 563,159 | 597 per sq mi |
| 7 | Chester County | 557,116 | 742 per sq mi |
| 8 | York County | 473,197 | 523 per sq mi |
| 9 | Berks County | 440,072 | 514 per sq mi |
| 10 | Lehigh County | 384,383 | 1,113 per sq mi |
And the smallest
More on Pennsylvania
Rebuilt from source data 30 August 2026. How these figures are produced.