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

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zipcodes.pro — STATE/MO/COUNTY/WASHINGTON

Washington County, MO ZIP codes

There are 10 ZIP codes in Washington County, MO, in 10 towns, from 63030 to 63674. The largest are 63664 (Potosi), 63630 (Cadet) and 63660 (Mineral Point). 2 more cross into it from neighbouring counties: 63080 and 65441.

The county seat is Potosi.

ZIP codes
10
Partly in it
2 more
Towns
10
County seat
Potosi
County FIPS
29221
Population
23,470
Median household income
$56,043
Land area
760 sq mi

Washington County ZIP codes by town

Potosi (county seat)
63664

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 Washington County

These ZIP codes lie mostly in a neighbouring county but each cover a twentieth or more of Washington County.

Map of Washington County ZIP codes

63030630716362263626636306363163648636606366463674

The ZIP codes of Washington 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.

Washington County in numbers

About 23,470 people live in Washington County, in 8,920 households, the 47th most populous of Missouri's 115 counties. The median household income is $56,043 a year, 21% below the Missouri median of $70,702 (US: $80,734). The median owner-occupied home is valued at $129,400 (44% below the Missouri median), and median gross rent is $684 a month. The median age is 40.7; 11.7% of adults 25 and over hold a bachelor's degree or higher (32.4% across Missouri); the average commute takes 38 minutes.

Population23,470Washington23,470
Households8,920Washington8,920
Median age40.7Washington40.7Missouri39.0US 38.9
Median household income$56,043Washington$56,043Missouri$70,702US $80,734
Median home value$129,400Washington$129,400Missouri$230,300US $332,700
Median gross rent$684Washington$684Missouri$1,033US $1,413
Bachelor's degree or higher11.7%Washington11.7%Missouri32.4%US 35.7%
Mean commute38.4 minWashington38.4 minMissouri23.5 minUS 26.4 min
Population density31 / sq miWashington31 / 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 Washington County

Largest towns in Washington County
TownZIP codesPopulation
Cadet 1 4,006
Potosi 1 2,544
Richwoods 1 1,113
Belgrade 1 764
Irondale 1 622
Blackwell 1 588
Fletcher 1 557
Mineral Point 1 324
Caledonia 1 209
Tiff 1 48

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 Washington County.

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

Every ZIP code in Washington County, with figures

ZIP codes in Washington County
ZIP City Type Population Median income Median home
63030 Fletcher , MO Standard 557 $91,042 $183,300
63071 Richwoods , MO Standard 1,113 $44,853 $122,900
63622 Belgrade , MO Standard 764 $31,750 —
63626 Blackwell , MO Standard 588 $82,599 $181,500
63630 Cadet , MO Standard 4,006 $52,482 $149,800
63631 Caledonia , MO Standard 544 $74,211 $127,500
63648 Irondale , MO Standard 1,858 $51,765 $99,500
63660 Mineral Point , MO Standard 2,784 $51,410 $119,700
63664 Potosi , MO Standard 9,693 $61,216 $125,100
63674 Tiff , MO Standard 48 — —

Cite this page

zipcodes.pro. “Washington County ZIP codes.” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/state/mo/county/washington

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