Zip Code | City | Population |
|---|---|---|
| 16001 | Butler | 39,808 |
| 16066 | Cranberry Township | 33,071 |
| 16046 | Mars | 18,772 |
| 16002 | Butler | 15,944 |
| 16057 | Slippery Rock | 15,067 |
| 16059 | Valencia | 9,394 |
| 16055 | Sarver | 8,548 |
| 16063 | Zelienople | 8,128 |
| 16033 | Evans City | 7,376 |
| 16025 | Chicora | 4,858 |
| 16037 | Harmony | 4,709 |
| 16056 | Saxonburg | 4,620 |
| 16023 | Cabot | 4,387 |
| 16053 | Renfrew | 3,478 |
| 16038 | Harrisville | 3,214 |
| 16051 | Portersville | 3,035 |
| 16061 | West Sunbury | 2,705 |
| 16052 | Prospect | 2,321 |
| 16041 | Karns City | 2,105 |
| 16034 | Fenelton | 1,831 |
| 16020 | Boyers | 1,190 |
| 16040 | Hilliards | 1,066 |
| 16045 | Lyndora | 999 |
| 16050 | Petrolia | 931 |
| 16029 | East Butler | 906 |
| 16027 | Connoquenessing | 392 |
| 16030 | Eau Claire | 327 |
| 16024 | Callery | 291 |
| 16022 | Bruin | 279 |
| 16048 | North Washington | 221 |
| 16035 | Forestville | 141 |