Every ZIP code in the United States, with weather, radar, trivia and the numbers behind it. Five digits since 1963!

ZIP stands for Zone Improvement Plan. The codes went live on July 1, 1963.The lowest ZIP code is 00501 — the IRS in Holtsville, New York.The highest ZIP code is 99950, in Ketchikan, Alaska.Type 07734 into a calculator and turn it upside down: hELLO. It is Keansburg, New Jersey.12345 belongs to one company: General Electric in Schenectady, New York.The first digit is a region: 0 is New England and New Jersey, 9 is the West Coast, Alaska and Hawaii.Mr. ZIP, the cartoon mailman, was the mascot that sold the idea to America.ZIP+4 arrived in 1983 and can narrow a ZIP down to one side of one block.A ZIP code is a mail route, not a place: plenty of them cross county and even state lines.Play ZIP Hunt: guess the secret ZIP code of the day in six tries.
zipcodes.pro — STATE/IL/COUNTY/WILLIAMSON

Williamson County, IL ZIP codes

There are 12 ZIP codes in Williamson County, IL, in 12 towns, from 62841 to 62974. The largest are 62959 (Marion), 62948 (Herrin) and 62918 (Carterville). 1 more crosses into it from a neighbouring county: 62890.

The county seat is Marion.

ZIP codes
12
Partly in it
1 more
Towns
12
County seat
Marion
County FIPS
17199
Population
66,876
Median household income
$65,604
Land area
420 sq mi
Area codes
618, 730
Metro area
Marion-Herrin

Williamson County ZIP codes by town

Marion (county seat)
62959

Each ZIP code is listed under the county most of its land lies in and the town the Postal Service names it for; a ZIP code's own page shows exactly how it is split.

ZIP codes partly in Williamson County

This ZIP code lies mostly in a neighbouring county but covers a twentieth or more of Williamson County.

Map of Williamson County ZIP codes

628416290262915629186292162922629336294862949629516295962974

The ZIP codes of Williamson County, shaded. Outlines are Census ZIP Code Tabulation Areas (2020), which approximate the mail routes; PO-box and single-address codes have no area and are not drawn. Click any area to open its ZIP code.

Williamson County in numbers

About 66,876 people live in Williamson County, in 28,983 households, the 22nd most populous of Illinois's 102 counties. The median household income is $65,604 a year, 21% below the Illinois median of $83,390 (US: $80,734). The median owner-occupied home is valued at $156,400 (41% below the Illinois median), and median gross rent is $930 a month. The median age is 41.6; 26.2% of adults 25 and over hold a bachelor's degree or higher (37.8% across Illinois); the average commute takes 24 minutes.

Population66,876Williamson66,876
Households28,983Williamson28,983
Median age41.6Williamson41.6Illinois39.0US 38.9
Median household income$65,604Williamson$65,604Illinois$83,390US $80,734
Median home value$156,400Williamson$156,400Illinois$263,300US $332,700
Median gross rent$930Williamson$930Illinois$1,274US $1,413
Bachelor's degree or higher26.2%Williamson26.2%Illinois37.8%US 35.7%
Mean commute23.5 minWilliamson23.5 minIllinois27.8 minUS 26.4 min
Population density159 / sq miWilliamson159 / sq mi

U.S. Census Bureau, American Community Survey 2020–2024 5-year estimates. Survey estimates carry margins of error, wider for small places. Sources and methods.

Largest towns in Williamson County

Largest towns in Williamson County
TownZIP codesPopulation
Carbondale 1 22,158
Marion 1 16,836
Herrin 1 12,226
Carterville 1 5,818
Johnston City 1 3,327
Cambria 1 1,300
Energy 1 1,050
Hurst 1 700
Pittsburg 1 682
Creal Springs 1 324
Colp 1 223
Freeman Spur 1 149

Population of the census place of that name where there is one, otherwise of the ZIP codes the Postal Service addresses by it. A town's ZIP codes can reach past the county line.

Neighbouring counties

Counties that share a ZIP code with Williamson County.

Not sure you are in Williamson County? What county am I in? answers from your location, near a county line included.

Every ZIP code in Williamson County, with figures

ZIP codes in Williamson County
ZIP City Type Population Median income Median home
62841 Freeman Spur , IL Standard 118 $31,750 $60,600
62902 Carbondale , IL Standard 4,135 $84,223 $207,800
62915 Cambria , IL Standard 384 $31,875 $106,700
62918 Carterville , IL Standard 10,658 $70,920 $200,200
62921 Colp , IL Standard 233 — $75,000
62922 Creal Springs , IL Standard 2,608 $74,245 $175,100
62933 Energy , IL Standard 1,101 $67,794 $156,100
62948 Herrin , IL Standard 12,758 $60,975 $116,700
62949 Hurst , IL Standard 702 $37,308 $74,500
62951 Johnston City , IL Standard 5,342 $50,657 $99,700
62959 Marion , IL Standard 27,793 $71,063 $174,800
62974 Pittsburg , IL Standard 1,536 $64,107 $199,100

Cite this page

zipcodes.pro. “Williamson County ZIP codes.” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/state/il/county/williamson

Underlying data is public domain or openly licensed — sources, vintages and licences.