Zip Code | City | Population |
|---|---|---|
| 16301 | Oil City | 15,178 |
| 16323 | Franklin | 14,934 |
| 16354 | Titusville | 10,225 |
| 16346 | Seneca | 3,138 |
| 16373 | Emlenton | 3,050 |
| 16342 | Polk | 2,359 |
| 16341 | Pleasantville | 1,862 |
| 16374 | Kennerdell | 1,725 |
| 16317 | Cooperstown | 1,404 |
| 16364 | Venus | 1,343 |
| 16319 | Cranberry | 1,137 |
| 16362 | Utica | 951 |
| 16343 | Reno | 550 |
| 16344 | Rouseville | 521 |
| 16372 | Clintonville | 504 |