| Locality | Post Code |
|---|---|
| Annandale, Butler | 16020 |
| Barkeyville, Butler | 16038 |
| Boyers, Butler | 16020 |
| Branchton, Butler | 16021 |
| Bruin, Butler | 16022 |
| Butler, Butler | 16001, 16002 |
| Cabot, Butler | 16023 |
| Callery, Butler | 16024 |
| Chicora, Butler | 16025 |
| Connoquenessing, Butler | 16027 |
| Cranberry Township, Butler | 16066 |
| East Butler, Butler | 16029 |
| Eau Claire, Butler | 16030 |
| Emlenton, Butler | 16373 |
| Evans City, Butler | 16033 |
| Fenelton, Butler | 16034 |
| Forestville, Butler | 16035 |
| Freeport, Butler | 16229 |
| Harmony, Butler | 16037 |
| Harrisville, Butler | 16038 |
| Herman, Butler | 16039 |
| Hilliards, Butler | 16040 |
| Karns City, Butler | 16041 |
| Lyndora, Butler | 16045 |
| Mars, Butler | 16046 |
| Marwood, Butler | 16023 |