| Castelnau-Durban | |
| Commune Status: | Commune |
| Arrondissement: | Saint-Girons |
| Canton: | Couserans Est |
| Insee: | 09082 |
| Postal Code: | 09420 |
| Mayor: | Marie-Pierre Eychenne[1] |
| Term: | 2020 - 2026 |
| Coordinates: | 43.0019°N 1.3425°W |
| Elevation M: | 410 |
| Elevation Min M: | 361 |
| Elevation Max M: | 931 |
| Area Km2: | 13.18 |
Castelnau-Durban (in French pronounced as /kastɛlno dyʁbɑ̃/; Occitan (post 1500);: Castèthnau de Durban) is a commune in the Ariège department in southwestern France.