Westerdam is een straat te Midsland in de gemeente Terschelling en is gelegen in de Nederlandse provincie Friesland.
| Postcode | Huisnummers |
|---|---|
| 8891 GL | 45, 47, 49, 51, 53, 55, 57, 59, 61, 63, 65, 43, 41, 39, 37, 35, 33, 31, 31D, 31C, 31B, 31A, 29, 27, 25, 25A, 21, 19, 17, 15, 13, 9, 7, 5, 3; |
| 8891 GM | 2, 4A, 4, 6, 8, 10, 12A, 12B, 12, 14, 16A, 16, 18, 20A, 20 1, 20 2, 20, 22, 24, 26 1, 26 2, 26; |