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County ZIP codes · Kentucky · FIPS 21157

Marshall County, KY ZIP Codes

Marshall County, Kentucky has 8 ZIP codes (Census 2020 ZCTA-county file; GeoNames postal codes, October 2026), all residential. 4 of the residential ones lie mainly in Marshall County and 4 mainly in a neighboring county; 6 cross the county line. Median household income ranges from $48,664 in 42066 (Mayfield) to $70,067 in 42025 (Benton) (Census Bureau, ACS 2020-2024).

  • ACS2020-24
  • Census2020

Where are the ZIP codes of Marshall County?

42025 · Benton: $70k42029 · Calvert City: $64k42036 · Dexter: $98k42044 · Gilbertsville: $57k42048 · Hardin: $56k42054 · Kirksey: $59k42066 · Mayfield: $49k42082 · Symsonia: $67k420254206642029420544204442048420364208242025 · Benton: $70k42029 · Calvert City: $64k42036 · Dexter: $98k42044 · Gilbertsville: $57k42048 · Hardin: $56k42054 · Kirksey: $59k42066 · Mayfield: $49k42082 · Symsonia: $67k420254206642029420544204442048420364208242025 · Benton: $70k42029 · Calvert City: $64k42036 · Dexter: $98k42044 · Gilbertsville: $57k42048 · Hardin: $56k42054 · Kirksey: $59k42066 · Mayfield: $49k42082 · Symsonia: $67k4202542066420294205442044420484203642082
The residential ZIP codes of Marshall 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?

They carry 8 postal town names: Mayfield, Benton, Calvert City, Gilbertsville, Hardin, Symsonia, Dexter, Kirksey.

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

All 8 residential ZIP codes in Marshall County

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

Residential ZIP codes mainly in Marshall County, largest first; "In this county" is the share of the ZIP's land in the county
In this county
42025 Benton 19,941 100 $70k $172k 96%
42029 Calvert City 5,552 121 $64k $154k 100%
42044 Gilbertsville 3,894 165 $57k $271k 100%
42048 Hardin 2,083 78 $56k $139k 93%

Partly in Marshall County

Residential ZIP codes mainly in another county that reach at least 1% into Marshall County, by their share here
In this county
42082 Symsonia 1,803 65 $67k $223k 31%
42054 Kirksey 837 25 $59k $160k 10%
42066 Mayfield 23,917 110 $49k $146k 2%
42036 Dexter 1,194 43 $98k $120k 1%

Download the 8 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 Marshall County extend into another county. A ZIP code follows mail routes, not county borders.

Share of each ZIP code's land in Marshall County and in the neighboring counties
ZIPIn MarshallElsewhere
420662%Graves County 98%
4202596%Graves County 2%; Calloway County 2%
4204893%Calloway County 7%
4208231%Graves County 55%; McCracken County 14%
420361%Calloway County 99%
4205410%Calloway County 86%; Graves County 4%

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

Which first three digits do Marshall County'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 Marshall County starts with 420.

Three-digit prefixes of Marshall 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 Marshall County's
PrefixSectional centerHereAll codes
420 Evansville, IN (SCF 476) 8 52

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