| ZIP Codes: | 24 ZIP Codes (23 Standard, 1 PO Box, 0 Unique) [See All] |
| Area Code: | 712 |
| Timezone: | Central (GMT -06:00) |
| Local Time: | 2:11:55 PM |
| Population: | 107,547 [See All] |
| FIPS: | 19193 |
| CBSA: | Sioux City, IA-NE-SD |
| Land Area: | 1,003 sq mi |
| Water Area: | 6 sq mi |
| Coordinates: | 42.4202, -96.1646 |
| Quick Link: |
107,547 residents live across 24 ZIPs covering 1,003 sq mi, served by 16 distinct USPS-recognized cities.
Population moved from 104,053 to 107,502 from 2014 to 2024 — a +3.3% change. 10 ZIPs gained residents, 12 lost.
The county's wealthiest ZIP 51054 (Sergeant Bluff, $119,716 median) and poorest ZIP 51101 (Sioux City, $15,300) are 8.6 miles apart — a 7.8× income gap across local geography.
Median home values vary 3.5× across this county — from $89,400 in 51016 (Correctionville) to $314,900 in 51018 (Cushing).
Density varies 341× across the county — from 9 people/sq mi in 51026 (Hornick) to 3,039 in 51104 (Sioux City).
Most of the decade's growth concentrated around Sioux City — top growth ZIPs averaged +37.1% over the past ten years ( 51101 , 51018 and 51109 ).
Educational attainment ranges from 3.4% bachelor's+ in 51109 (Sioux City) to 36.8% in 51054 (Sergeant Bluff) — the breadth of educational profiles across the area.
Within Iowa, this is the #6 most populous of 99 counties and ranks #31 for median household income .
Weighted by population, the typical household earns about $74,622 across the county — reflecting what a typical resident sees, not a simple ZIP average.
24.3% of adults age 25+ hold a bachelor's degree or higher (16,816 of 69,062 reporting).
23 Standard delivery, 1 PO Box only, 0 single-entity Unique ZIPs serve this county.
Median household income spans 7.8× between the wealthiest and poorest ZIPs — a sign of significant intra-county inequality.
| ZIP | City | Type | Population | Median Income | Area (sq mi) | 10-yr Growth |
|---|---|---|---|---|---|---|
| 51106 | Sioux City | Standard | 28,592 | $78,434 | 31.3 | 9.4% |
| 51104 | Sioux City | Standard | 23,197 | $75,362 | 7.6 | -0.1% |
| 51103 | Sioux City | Standard | 16,895 | $58,197 | 12.2 | -4.0% |
| 51105 | Sioux City | Standard | 10,415 | $51,786 | 6.1 | 10.0% |
| 51108 | Sioux City | Standard | 5,960 | $81,205 | 46.9 | 6.8% |
| 51054 | Sergeant Bluff | Standard | 5,583 | $119,716 | 41.8 | 7.7% |
| 51109 | Sioux City | Standard | 3,606 | $79,034 | 18.3 | 23.3% |
| 51039 | Moville | Standard | 2,845 | $110,000 | 89.1 | 17.5% |
| 51030 | Lawton | Standard | 1,468 | $86,167 | 56.6 | -11.5% |
| 51055 | Sloan | Standard | 1,346 | $72,143 | 63.7 | -1.3% |
| 51016 | Correctionville | Standard | 1,080 | $51,875 | 99.3 | -14.8% |
| 51052 | Salix | Standard | 1,050 | $108,750 | 63.0 | 15.6% |
| 51101 | Sioux City | Standard | 1,031 | $15,300 | 1.4 | 46.9% |
| 51026 | Hornick | Standard | 910 | $80,500 | 102.1 | 2.6% |
| 51004 | Anthon | Standard | 858 | $43,882 | 80.6 | -35.0% |
| 51007 | Bronson | Standard | 691 | $117,125 | 35.2 | -5.3% |
| 51018 | Cushing | Standard | 542 | $60,833 | 35.7 | 41.1% |
| 51019 | Danbury | Standard | 448 | $75,000 | 92.1 | -42.9% |
| 51048 | Pierson | Standard | 435 | $83,158 | 44.3 | -29.7% |
| 51056 | Smithland | Standard | 346 | $103,313 | 34.0 | -25.4% |
| 51044 | Oto | Standard | 165 | $90,417 | 33.2 | -7.8% |
| 51015 | Climbing Hill | Standard | 45 | $87,500 | 1.3 | — |
| 51111 | Sioux City | Standard | 39 | — | 7.5 | -85.5% |
| 51102 | Sioux City | PO Box | — | — | 0.0 | — |