Identifiers: city · borough · CDP
| Rank | Community | Population |
|---|---|---|
| 1 | Oil City (city), PA | 9,613 |
| 2 | Grove City (borough), PA | 7,871 |
| 3 | Franklin (city), PA | 6,077 |
| 4 | Titusville (city), PA | 5,262 |
| 5 | Sugarcreek (borough), PA | 4,775 |
| 6 | Hasson Heights (CDP), PA | 1,229 |
| 7 | Woodland Heights (CDP), PA | 1,180 |
| 8 | Cochranton (borough), PA | 1,118 |
| 9 | Seneca (CDP), PA | 1,011 |
| 10 | Harrisville (borough), PA | 819 |
| 11 | Sandy Lake (borough), PA | 649 |
| 12 | Polk (borough), PA | 634 |
| 13 | Emlenton (borough), PA | 614 |
| 14 | Rouseville (borough), PA | 457 |
| 15 | Clintonville (borough), PA | 439 |
| 16 | Cooperstown (borough), PA | 399 |
| 17 | St. Petersburg (borough), PA | 336 |
| 18 | Eau Claire (borough), PA | 307 |
| 19 | Jackson Center (borough), PA | 194 |
| 20 | Barkeyville (borough), PA | 188 |