| Sg. Indef. | ísfjall |
| Sg. Def. | ísfjallið |
| Pl. Indef. | ísfjøll |
| Pl. Def. | ísfjøllini |
| Sg. Indef. | ísfjals |
| Sg. Def. | ísfjalsins |
| Pl. Indef. | ísfjalla |
| Pl. Def. | ísfjallanna |
| Sg. Indef. | ísfjalli |
| Sg. Def. | ísfjallinum |
| Pl. Indef. | ísfjøllum |
| Pl. Def. | ísfjøllunum |
| Sg. Indef. | ísfjall |
| Sg. Def. | ísfjallið |
| Pl. Indef. | ísfjøll |
| Pl. Def. | ísfjøllini |