Washington County, Missouri ZIP Codes

Zip Code
City
Population ↓
63664Potosi9,693
63630Cadet4,006
63660Mineral Point2,784
63648Irondale1,858
63071Richwoods1,113
63622Belgrade764
63626Blackwell588
63030Fletcher557
63631Caledonia544
63674Tiff48

Overview of ZIP Codes in Washington County

ZCTAs are geographic areas created by the US Census Bureau to approximate the delivery areas of ZIP Codes for statistical analysis. While ZCTAs use the same five-digit codes as ZIP Codes, they represent defined geographic areas that may not exactly match the mail delivery routes of ZIP Codes.
10
ZIP Codes

The data shown reflect ZCTAs from the US Census. As of 2025, there are 10 ZCTAs in Washington County, Missouri (US Census).

Sources

  1. US Census: 2025 Gazetteer Files
  2. US Census: ZIP Code Tabulation Areas (ZCTAs)

Recommended Reading