District of Columbia ZIP codes

District of Columbia holds 277 ZIP codes between 20001 and 56972. The tables rank the places and counties with the most codes; the guide below decodes the numbering.

Places with the most ZIP codes in District of Columbia

District of Columbia counties by ZIP count

Reading a District of Columbia ZIP code

District of Columbia holds 277 ZIP codes between 20001 and 56972, spread over 1 counties. Washington leads the state with 271 codes, ahead of Washington Navy Yard with 5. Every code here opens with digits 2 to 5: that opening number is the national postal region District of Columbia belongs to, the next two digits name the sectional center that sorts the mail, and the final two point to the local office. A ZIP+4 suffix narrows delivery to a block face. Boundaries follow carrier routes rather than city limits, which is why Washington spreads across 271 codes while some rural codes cross county lines.

Source: GeoNames postal dataset (CC BY 4.0), snapshot of 2026-07-09. Counts cover standard delivery ZIPs listed for District of Columbia; unique and PO box codes may add to these totals.

Last updated: 2026-07-09 · Methodology and sources