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County ZIP codes · Iowa · FIPS 19149

Plymouth County, IA ZIP Codes

Plymouth County, Iowa has 14 ZIP codes (Census 2020 ZCTA-county file; GeoNames postal codes, October 2026), all residential. 11 of the residential ones lie mainly in Plymouth County and 3 mainly in a neighboring county; 9 cross the county line. Median household income ranges from $75,404 in 51001 (Akron) to $114,219 in 51024 (Hinton) (Census Bureau, ACS 2020-2024).

  • ACS2020-24
  • Census2020

Where are the ZIP codes of Plymouth County?

51001 · Akron: $75k51008 · Brunsville: $45k51022 · Granville: $97k51024 · Hinton: $114k51027 · Ireton: $101k51028 · Kingsley: $78k51031 · Le Mars: $77k51038 · Merrill: $96k51045 · Oyens: $114k51048 · Pierson: $83k51050 · Remsen: $93k51062 · Westfield: –51108 · Sioux City: $81k51109 · Sioux City: $79k51031510015102851027510505102451038510225106251108510485110951001 · Akron: $75k51008 · Brunsville: $45k51022 · Granville: $97k51024 · Hinton: $114k51027 · Ireton: $101k51028 · Kingsley: $78k51031 · Le Mars: $77k51038 · Merrill: $96k51045 · Oyens: $114k51048 · Pierson: $83k51050 · Remsen: $93k51062 · Westfield: –51108 · Sioux City: $81k51109 · Sioux City: $79k51031510015102851027510505102451038510225106251108510485110951001 · Akron: $75k51008 · Brunsville: $45k51022 · Granville: $97k51024 · Hinton: $114k51027 · Ireton: $101k51028 · Kingsley: $78k51031 · Le Mars: $77k51038 · Merrill: $96k51045 · Oyens: $114k51048 · Pierson: $83k51050 · Remsen: $93k51062 · Westfield: –51108 · Sioux City: $81k51109 · Sioux City: $79k51031510015102851027510505102451038510225106251108
The residential ZIP codes of Plymouth County (whole outlines, including the parts in neighboring counties), shaded by median household income in national fifths (ACS 2020-2024). <$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 its ZIP codes?

The middle half of its ranked ZIP codes (1,000+ people living in households) report median household incomes between $76,525 and $95,893.

They carry 13 postal town names.

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

All 14 residential ZIP codes in Plymouth County

11 ZIP codes lie mainly in Plymouth County; 3 more reach into it from a neighboring county and follow the first table.

Residential ZIP codes mainly in Plymouth County, largest first; "In this county" is the share of the ZIP's land in the county
In this county
51031 Le Mars 12,808 55 $77k $223k 99%
51108 Sioux City 5,960 130 $81k $170k 53%
51109 Sioux City 3,606 205 $79k $131k 90%
51050 Remsen 2,962 21 $93k $220k 99%
51001 Akron 2,342 14 $75k $193k 60%
51028 Kingsley 2,191 18 $78k $220k 80%
51024 Hinton 2,081 24 $114k $348k 100%
51038 Merrill 1,449 16 $96k $183k 100%
51062 Westfield 503 9 – $250k 100%
51008 Brunsville 210 745 $45k $129k 100%
51045 Oyens 66 1,000 $114k $170k 100%

Partly in Plymouth County

Residential ZIP codes mainly in another county that reach at least 1% into Plymouth County, by their share here
In this county
51027 Ireton 1,280 14 $101k $227k 16%
51048 Pierson 435 12 $83k $103k 11%
51022 Granville 960 13 $97k $175k 3%

Download the 14 ZIP codes as CSV

Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates; county shares by land area (Census 2020 ZCTA-county relationship file).

Which ZIP codes cross the county line?

9 ZIP codes of Plymouth County extend into another county. A ZIP code follows mail routes, not county borders.

Share of each ZIP code's land in Plymouth County and in the neighboring counties
ZIPIn PlymouthElsewhere
5103199%Sioux County 1%
5110853%Woodbury County 47%
5110990%Woodbury County 10%
5105099%Sioux County 1%
5100160%Union County 40%
5102880%Woodbury County 20%
5102716%Sioux County 84%
510223%O'Brien County 58%; Sioux County 40%
5104811%Woodbury County 49%; Cherokee County 40%

Source: U.S. Census Bureau, 2020 ZCTA-county relationship file (shares of land area).

Which first three digits do Plymouth County's ZIP codes use?

The first three digits of a ZIP code name the sectional center, the mail processing plant that sorts it. Plymouth County's ZIP codes use 2 prefixes: 510 and 511.

Three-digit prefixes of Plymouth County'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 Plymouth County's
PrefixSectional centerHereAll codes
510 Sioux Falls, SD (SCF 570) 12 55
511 Sioux Falls, SD (SCF 570) 2 9

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