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County ZIP codes · South Dakota · FIPS 46127

Union County, SD ZIP Codes

Union County, South Dakota has 9 ZIP codes (Census 2020 ZCTA-county file; GeoNames postal codes, October 2026), all residential. 4 of the residential ones lie mainly in Union County and 5 mainly in a neighboring county; 6 cross the county line. Median household income ranges from $69,531 in 57001 (Alcester) to $94,839 in 57025 (Elk Point) (Census Bureau, ACS 2020-2024).

  • ACS2020-24
  • Census2020

Where are the ZIP codes of Union County?

51001 · Akron: $75k51023 · Hawarden: $80k57001 · Alcester: $70k57004 · Beresford: $89k57010 · Burbank: $94k57025 · Elk Point: $95k57034 · Hudson: $90k57038 · Jefferson: $106k57049 · North Sioux City: $93k57004510015702551023570015703457010570385704951001 · Akron: $75k51023 · Hawarden: $80k57001 · Alcester: $70k57004 · Beresford: $89k57010 · Burbank: $94k57025 · Elk Point: $95k57034 · Hudson: $90k57038 · Jefferson: $106k57049 · North Sioux City: $93k57004510015702551023570015703457010570385704951001 · Akron: $75k51023 · Hawarden: $80k57001 · Alcester: $70k57004 · Beresford: $89k57010 · Burbank: $94k57025 · Elk Point: $95k57034 · Hudson: $90k57038 · Jefferson: $106k57049 · North Sioux City: $93k5700451001570255102357001570345701057038
The residential ZIP codes of Union 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 $75,404 and $88,750.

They carry 9 postal town names.

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

All 9 residential ZIP codes in Union County

4 ZIP codes lie mainly in Union County; 5 more reach into it from a neighboring county and follow the first table.

Residential ZIP codes mainly in Union County, largest first; "In this county" is the share of the ZIP's land in the county
In this county
57049 North Sioux City 7,962 562 $93k $432k 100%
57025 Elk Point 3,120 25 $95k $238k 100%
57038 Jefferson 1,796 36 $106k $332k 100%
57001 Alcester 1,540 16 $70k $177k 93%

Partly in Union County

Residential ZIP codes mainly in another county that reach at least 1% into Union County, by their share here
In this county
51001 Akron 2,342 14 $75k $193k 40%
57010 Burbank 755 12 $94k $296k 31%
51023 Hawarden 3,473 29 $80k $173k 30%
57004 Beresford 3,834 20 $89k $264k 27%
57034 Hudson 661 9 $90k $194k 9%

Download the 9 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?

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

Share of each ZIP code's land in Union County and in the neighboring counties
ZIPIn UnionElsewhere
5700427%Lincoln County 47%; Clay County 26%
5102330%Sioux County 70%
5100140%Plymouth County 60%
5700193%Lincoln County 7%
5701031%Clay County 69%
570349%Lincoln County 84%; Sioux County 8%

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

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

The first three digits of a ZIP code name the sectional center, the mail processing plant that sorts it. Union County's ZIP codes use 2 prefixes: 510 and 570.

Three-digit prefixes of Union 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 Union County's
PrefixSectional centerHereAll codes
510 Sioux Falls, SD (SCF 570) 2 55
570 Sioux Falls, SD (SCF 570) 7 69

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