ZIP Codes in Sioux City, IA
Sioux City uses 8 ZIP codes, all in Woodbury, Plymouth Counties. Pick one below for details, or look up the full nine-digit ZIP+4 for a specific street address.
All 8 Sioux City ZIP codes
| ZIP | Type | County | Population |
|---|---|---|---|
| 51101 | standard | Woodbury | 1,031 |
| 51103 | standard | Woodbury | 16,895 |
| 51104 | standard | Woodbury | 23,197 |
| 51105 | standard | Woodbury | 10,415 |
| 51106 | standard | Woodbury | 28,592 |
| 51108 | standard | Plymouth | 5,960 |
| 51109 | standard | Plymouth | 3,606 |
| 51111 | standard | Woodbury | 39 |
Finding a ZIP+4 in Sioux City
Knowing which of these 8 ZIP codes covers an address only gets you partway. The four-digit extension identifies the specific delivery point — typically one side of one block. Two houses facing each other on the same Sioux City street almost always have different ZIP+4 codes even though they share all five leading digits.
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