| Castaignos-Souslens | |
| Commune Status: | Commune |
| Arrondissement: | Dax |
| Canton: | Coteau de Chalosse |
| Insee: | 40069 |
| Postal Code: | 40700 |
| Mayor: | Georges Lacave[1] |
| Term: | 2020 - 2026 |
| Coordinates: | 43.5872°N -0.6497°W |
| Elevation M: | 144 |
| Elevation Min M: | 45 |
| Elevation Max M: | 146 |
| Area Km2: | 7.45 |
Castaignos-Souslens is a commune in the Landes department in Nouvelle-Aquitaine in southwestern France.[2]