Zip Code | City | Population |
|---|---|---|
| 18102 | Allentown | 51,640 |
| 18103 | Allentown | 48,344 |
| 18104 | Allentown | 46,259 |
| 18018 | Bethlehem | 31,479 |
| 18052 | Whitehall | 29,286 |
| 18062 | Macungie | 26,722 |
| 18049 | Emmaus | 18,727 |
| 18109 | Allentown | 17,745 |
| 18036 | Coopersburg | 14,532 |
| 18031 | Breinigsville | 12,337 |
| 18080 | Slatington | 11,251 |
| 18032 | Catasauqua | 9,468 |
| 18034 | Center Valley | 9,228 |
| 18069 | Orefield | 8,593 |
| 18078 | Schnecksville | 7,543 |
| 18037 | Coplay | 7,360 |
| 18106 | Allentown | 6,759 |
| 18101 | Allentown | 5,673 |
| 18066 | New Tripoli | 5,612 |
| 18051 | Fogelsville | 3,390 |
| 18092 | Zionsville | 3,078 |
| 18053 | Germansville | 2,565 |
| 18087 | Trexlertown | 762 |
| 18059 | Laurys Station | 728 |
| 18079 | Slatedale | 550 |
| 18065 | Neffs | 271 |
| 18046 | East Texas | 142 |
| 18195 | Allentown | 0 |