FIRMS code

Q537 U.S. POST OFFICE

Deleted Inspection facility

This code is deleted in CBP's FIRMS list. Don't use it on new filings. FIRMSapi keeps deleted codes so lookups of old paperwork still resolve; check the port listing for a replacement.

Facility details

FIRMS code: Q537
Name: U.S. POST OFFICE
Address: 710 AIRPORT RD, BAY 5&6
FLOWOOD, MS 39232
Status: Deleted (D)
Facility type: Inspection facility (05)
CBP port: Vicksburg, MS (2015)
CBP region: 5
Last changed: 2026-10-23
Data as of: 2026-10-23

Pre-filing validation

Validate Q537 before you file

Validation fails Q537: it's deleted, the reject ACE returns as 159. Search the port for an active replacement.

curl https://api.firmsapi.com/v1/validate \
  -H "x-api-key: $FIRMSAPI_KEY" -H "content-type: application/json" \
  -d '{"code":"Q537","port":"2015","use":"location_of_goods"}'

Get a free key Validation guide

Source: U.S. Customs and Border Protection FIRMS code list, data as of 2026-10-23. FIRMSapi is not affiliated with CBP; confirm bond status and filing details in ACE.