| Sg. Indef. | gosfjall |
| Sg. Def. | gosfjallið |
| Pl. Indef. | gosfjøll |
| Pl. Def. | gosfjøllini |
| Sg. Indef. | gosfjals |
| Sg. Def. | gosfjalsins |
| Pl. Indef. | gosfjalla |
| Pl. Def. | gosfjallanna |
| Sg. Indef. | gosfjalli |
| Sg. Def. | gosfjallinum |
| Pl. Indef. | gosfjøllum |
| Pl. Def. | gosfjøllunum |
| Sg. Indef. | gosfjall |
| Sg. Def. | gosfjallið |
| Pl. Indef. | gosfjøll |
| Pl. Def. | gosfjøllini |