The canton Fosses has 24 communes.
| Code | Name | Population ▼ |
|---|---|---|
| 95250 | Fosses | 10 570 |
| 95229 | Ézanville | 9 858 |
| 95205 | Écouen | 7 202 |
| 95652 | Viarmes | 5 558 |
| 95352 | Luzarches | 5 008 |
| 95509 | Puiseux-en-France | 3 765 |
| 95149 | Chaumontel | 3 332 |
| 95566 | Saint-Martin-du-Tertre | 2 689 |
| 95056 | Belloy-en-France | 2 250 |
| 95241 | Fontenay-en-Parisis | 2 219 |
| 95028 | Attainville | 1 904 |
| 95353 | Maffliers | 1 856 |
| 95594 | Seugy | 1 044 |
| 95395 | Le Mesnil-Aubry | 914 |
| 95660 | Villaines-sous-Bois | 778 |
| 95365 | Mareil-en-France | 734 |
| 95055 | Bellefontaine | 474 |
| 95316 | Jagny-sous-Bois | 269 |
| 95682 | Villiers-le-Sec | 205 |
| 95331 | Lassy | 196 |
| 95493 | Le Plessis-Luzarches | 152 |
| 95492 | Le Plessis-Gassot | 102 |
| 95144 | Châtenay-en-France | 68 |
| 95214 | Épinay-Champlâtreux | 57 |