| Place | Postal Code |
|---|---|
| Niederkassel, Köln) | 53859 |
| Postal Codes in Rhein-Sieg-Kreis | |
|---|---|
| Alfter | |
| Bad Honnef | |
| Bornheim | |
| Eitorf | |
| Hennef (Sieg) | |
| Königswinter | |
| Lohmar | |
| Meckenheim | |
| Much | |
| Neunkirchen-Seelscheid | |
| Niederkassel | |
| Rheinbach | |
| Ruppichteroth | |
| Sankt Augustin | |
| Siegburg | |
| Swisttal | |
| Troisdorf | |
| Wachtberg | |
| Windeck | |