Geocoding PO Box Addresses: What Works and What Doesn't

The Census Geocoder intentionally does not geocode PO Boxes. Here's what happens, how to detect them, and your options.

What we measured

Testing against the live API: PO Box 123, Washington, DC 20001 returns NO_MATCH, while the same city/ZIP with a street address matches fine. Rural route boxes (RR/HC) do match to the delivery area's county.

Practical options

• Filter PO Boxes before batch runs (regex ^PO BOX|P\.O\. BOX on the street line).
• Use the mailing city/ZIP with a street address from your own records.
• For ZIP-level fallback, a ZIP-to-county crosswalk is the honest resolution (ZIPs can span several counties).

Try it free

Data source: U.S. Census Bureau Geocoder (public domain). Timezone: tz-lookup (MIT).

FAQ

Does GeoFlow support PO Boxes?

Not for geocoding — no provider can place a PO Box on a map. We surface a clear NO_MATCH so you can segment those rows.