Oostenstein is een straat te Kollum in de gemeente Kollumerland en Nieuwkruisland en is gelegen in de Nederlandse provincie Friesland.
| Postcode | Huisnummers |
|---|---|
| 9291 GR | 50, 52, 54, 56, 58, 60, 48, 46, 44, 42, 40, 38, 36, 34, 32, 30, 28, 26, 24, 22, 20, 18, 16, 14, 12, 10, 8, 6, 4, 2; |
| 9291 GS | 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37, 39, 41, 43; |