County ZIP codes · Illinois · FIPS 17009

Brown County, IL ZIP Codes

Brown County, Illinois has 5 ZIP codes (Census 2020 ZCTA-county file; GeoNames postal codes, October 2026), all residential. 3 of the residential ones lie mainly in Brown County and 2 mainly in a neighboring county; 3 cross the county line. Median household income ranges from $66,000 in 62353 (Mount Sterling) to $76,903 in 62324 (Clayton) (Census Bureau, ACS 2020-2024).

ACS2020-24
Census2020

Where are the ZIP codes of Brown County?

The residential ZIP codes of Brown 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?

62353 · $66k62324 · $77k

They carry 5 postal town names: Mount Sterling, Clayton, Versailles, Timewell, Chambersburg.

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

All 5 residential ZIP codes in Brown County

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

Residential ZIP codes mainly in Brown County, largest first; "In this county" is the share of the ZIP's land in the county
						In this county
62353	Mount Sterling	5,066	27	$66k	$152k	98%
62378	Versailles	863	13	$70k	$151k	100%
62375	Timewell	383	8	$77k	$141k	100%

Partly in Brown County

Residential ZIP codes mainly in another county that reach at least 1% into Brown County, by their share here
						In this county
62324	Clayton	1,196	13	$77k	$97k	7%
62323	Chambersburg	198	5	$93k	$98k	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?

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

Share of each ZIP code's land in Brown County and in the neighboring counties
ZIP	In Brown	Elsewhere
62353	98%	Pike County1%
62324	7%	Adams County93%
62323	2%	Pike County98%

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

Which first three digits do Brown 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 Brown County starts with 623.

Three-digit prefixes of Brown 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 Brown County's
Prefix	Sectional center	Here	All codes
623	Springfield, IL (SCF 625)	5	54

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