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City ZIP codes · Iowa

Sioux City, IA ZIP Codes

9 ZIP codes use the postal name Sioux City, Iowa (Census 2020 ZCTAs and GeoNames postal codes, October 2026): 8 residential and 1 for PO boxes or a single organization. Median household income runs from $51,786 in 51105 to $81,205 in 51108, 1.6 times as much (Census Bureau, ACS 2020-2024). Sioux City's most populous ZIP code is 51106, with 28,592 people (ACS 2020-2024); 43% of its land is in the city of Sioux City.

  • ACS2020-24
  • Census2020
  • GeoNames2026

Where are Sioux City's ZIP codes?

51101: $15k median household income51103: $58k median household income51104: $75k median household income51105: $52k median household income51106: $78k median household income51108: $81k median household income51109: $79k median household income51111: – median household income511085110651109511035110551104511115110151101: $15k median household income51103: $58k median household income51104: $75k median household income51105: $52k median household income51106: $78k median household income51108: $81k median household income51109: $79k median household income51111: – median household income511085110651109511035110551104511115110151101: $15k median household income51103: $58k median household income51104: $75k median household income51105: $52k median household income51106: $78k median household income51108: $81k median household income51109: $79k median household income51111: – median household income51108511065110951103511055110451111
The 8 residential ZIP codes named Sioux City, shaded by median household income in national fifths (ACS 2020-2024). Select a ZIP to open it. <$54.1k$98.1k+no figure

Source: U.S. Census Bureau, 2020 ZCTA cartographic boundaries; ACS 2020-2024 5-year estimates (B19013).

How different are Sioux City's ZIP codes?

The highest median household income is in 51108 ($81,205), the lowest in 51105 ($51,786). Home values run from $96,200 in 51105 to $211,100 in 51104.

Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates (B19013, B25077, B01003).

All 8 residential ZIP codes of Sioux City

Residential ZIP codes with the postal name Sioux City, IA, largest first (ACS 2020-2024); sort by any column
County
51106 Woodbury County 28,592 854 $78k $200k
51104 Woodbury County 23,197 3,103 $75k $211k
51103 Woodbury County 16,895 1,400 $58k $143k
51105 Woodbury County 10,415 1,750 $52k $96k
51108 Plymouth County 5,960 130 $81k $170k
51109 Plymouth County 3,606 205 $79k $131k
51101 Woodbury County 1,031 857 $15k –
51111 Woodbury County 39 6 – –

Download the 9 ZIP codes as CSV

Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates; 2023 Gazetteer land areas (2020 ZCTAs); town names from simplemaps US ZIP Codes (CC BY 4.0) and GeoNames (CC BY 4.0).

PO Box and single-organization ZIP codes in Sioux City

1 ZIP code named Sioux City has no residential delivery area: post office boxes, or one organization (a large employer, an agency, a university) with its own code. The Census Bureau publishes no figures for them.

Sioux City, IA: ZIP codes without a residential area, for PO boxes or one organization (GeoNames postal codes; USPS does not publish openly which is which)
ZIPCounty
51102Woodbury County

Source: GeoNames postal codes (CC BY 4.0); a ZIP code with no Census ZCTA has no residential delivery area.

Which counties do Sioux City's ZIP codes reach?

Sioux City's residential ZIP codes lie in 2 counties: Woodbury County (6 ZIP codes mainly there), Plymouth County (2 ZIP codes mainly there).

Which first three digits do Sioux City's ZIP codes use?

The first three digits of a ZIP code name the sectional center, the mail processing plant that sorts it. Every ZIP code of Sioux City starts with 511.

Three-digit prefixes of Sioux City's ZIP codes, the sectional center for each (USPS labeling list L005, effective October 1, 2026) and how many of the prefix's codes are Sioux City's
PrefixSectional centerHereAll codes
511 Sioux Falls, SD (SCF 570) 9 9

All 9 ZIP codes that start with 511 are Sioux City's: 8 residential codes and 1 PO Box or unique code, sorted at Sioux Falls, SD (SCF 570).

Source: U.S. Postal Service, labeling list L005 (3-digit ZIP Code prefix groups, SCF sortation), effective October 1, 2026.