County ZIP codes · Montana · FIPS 30025

Fallon County, MT ZIP Codes

Fallon County, Montana has 5 ZIP codes (Census 2020 ZCTA-county file; GeoNames postal codes, October 2026), all residential. 3 of the residential ones lie mainly in Fallon County and 2 mainly in a neighboring county; 4 cross the county line.

ACS2020-24
Census2020

Where are the ZIP codes of Fallon County?

The residential ZIP codes of Fallon 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).

All 5 residential ZIP codes in Fallon County

3 ZIP codes lie mainly in Fallon County; 2 more reach into it from a neighboring county and follow the first table.

Residential ZIP codes mainly in Fallon County, largest first; "In this county" is the share of the ZIP's land in the county
						In this county
59313	Baker	2,111	2	$78k	$232k	94%
59344	Plevna	406	1	$111k	$288k	94%
59354	Willard	258	5	$64k	–	100%

Partly in Fallon County

Residential ZIP codes mainly in another county that reach at least 1% into Fallon County, by their share here
						In this county
59336	Ismay	220	0	$64k	$293k	28%
59353	Wibaux	1,204	1	$68k	$99k	2%

Download the 5 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?

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

Share of each ZIP code's land in Fallon County and in the neighboring counties
ZIP	In Fallon	Elsewhere
59313	94%	Carter County6%
59353	2%	Wibaux County84%; Dawson County14%
59344	94%	Carter County6%
59336	28%	Custer County65%; Carter County6%

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

Which first three digits do Fallon 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 Fallon County starts with 593.

Three-digit prefixes of Fallon 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 Fallon County's
Prefix	Sectional center	Here	All codes
593	Billings, MT (SCF 590)	5	31

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