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County ZIP codes · Montana · FIPS 30011

Carter County, MT ZIP Codes

Carter County, Montana has 10 ZIP codes (Census 2020 ZCTA-county file; GeoNames postal codes, October 2026), all residential. 4 of the residential ones lie mainly in Carter County and 6 mainly in a neighboring county; 6 cross the county line. Median household income ranges from $77,689 in 57717 (Belle Fourche) to $78,015 in 59313 (Baker) (Census Bureau, ACS 2020-2024).

  • ACS2020-24
  • Census2020

Where are the ZIP codes of Carter County?

57717 · Belle Fourche: $78k57724 · Camp Crook: $61k59311 · Alzada: $88k59313 · Baker: $78k59316 · Boyes: $49k59319 · Capitol: –59324 · Ekalaka: $57k59332 · Hammond: $32k59336 · Ismay: $64k59344 · Plevna: $111k5771759324593365931359311593325772459344593195931657717 · Belle Fourche: $78k57724 · Camp Crook: $61k59311 · Alzada: $88k59313 · Baker: $78k59316 · Boyes: $49k59319 · Capitol: –59324 · Ekalaka: $57k59332 · Hammond: $32k59336 · Ismay: $64k59344 · Plevna: $111k57717593245933659313593115933257724593445931957717 · Belle Fourche: $78k57724 · Camp Crook: $61k59311 · Alzada: $88k59313 · Baker: $78k59316 · Boyes: $49k59319 · Capitol: –59324 · Ekalaka: $57k59332 · Hammond: $32k59336 · Ismay: $64k59344 · Plevna: $111k5771759324593365931359311593325772459319
The residential ZIP codes of Carter 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 10 postal town names.

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

All 10 residential ZIP codes in Carter County

4 ZIP codes lie mainly in Carter County; 6 more reach into it from a neighboring county and follow the first table.

Residential ZIP codes mainly in Carter County, largest first; "In this county" is the share of the ZIP's land in the county
In this county
59324 Ekalaka 777 1 $57k $176k 100%
59311 Alzada 143 0 $88k – 100%
59332 Hammond 140 0 $32k – 100%
59319 Capitol 40 0 – – 100%

Partly in Carter County

Residential ZIP codes mainly in another county that reach at least 1% into Carter County, by their share here
In this county
57724 Camp Crook 167 0 $61k – 37%
59316 Boyes 15 0 $49k – 30%
57717 Belle Fourche 8,983 7 $78k $249k 10%
59313 Baker 2,111 2 $78k $232k 6%
59344 Plevna 406 1 $111k $288k 6%
59336 Ismay 220 0 $64k $293k 6%

Download the 10 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 Carter County extend into another county. A ZIP code follows mail routes, not county borders.

Share of each ZIP code's land in Carter County and in the neighboring counties
ZIPIn CarterElsewhere
5771710%Butte County65%; Crook County15%; Harding County9%
593136%Fallon County94%
593446%Fallon County94%
593366%Custer County65%; Fallon County28%
5772437%Harding County63%
5931630%Powder River County70%

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

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

The first three digits of a ZIP code name the sectional center, the mail processing plant that sorts it. Carter County's ZIP codes use 2 prefixes: 577 and 593.

Three-digit prefixes of Carter 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 Carter County's
PrefixSectional centerHereAll codes
577Rapid City, SD (SCF 577)258
593Billings, MT (SCF 590)831

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