Identifiers: CDP · city · borough
| Rank | Community | Population |
|---|---|---|
| 1 | Allison Park (CDP), PA | 21,864 |
| 2 | Butler (city), PA | 13,502 |
| 3 | Homeacre-Lyndora (CDP), PA | 6,721 |
| 4 | Shanor-Northvue (CDP), PA | 5,133 |
| 5 | Zelienople (borough), PA | 3,912 |
| 6 | Meridian (CDP), PA | 3,760 |
| 7 | Seven Fields (borough), PA | 2,919 |
| 8 | Gibsonia (CDP), PA | 2,785 |
| 9 | Bakerstown (CDP), PA | 2,745 |
| 10 | Meadowood (CDP), PA | 2,729 |
| 11 | Oak Hills (CDP), PA | 2,382 |
| 12 | Evans City (borough), PA | 1,737 |
| 13 | Mars (borough), PA | 1,458 |
| 14 | Saxonburg (borough), PA | 1,426 |
| 15 | Nixon (CDP), PA | 1,393 |
| 16 | Russellton (CDP), PA | 1,330 |
| 17 | Bradford Woods (borough), PA | 1,183 |
| 18 | Prospect (borough), PA | 1,123 |
| 19 | Curtisville (CDP), PA | 1,097 |
| 20 | Harmony (borough), PA | 942 |