Customs Port Code List for Imports and Exports

U.S. customs filings draw port codes from three different official lists, and picking the right one depends on the filing in front of you. Schedule D covers U.S. domestic ports and is published by the Census Bureau. Schedule K covers foreign seaports and is maintained by the U.S. Army Corps of Engineers with additions from CBP. UN/LOCODE covers ports, airports, rail and road terminals, and border crossings worldwide, and is published by the United Nations Economic Commission for Europe. This customs port code list guide walks through each system, where to pull the current version, and which one belongs on which form.

The Three Code Systems at a Glance

Schedule D identifies every U.S. customs district and port of entry where shipments are reportable. Codes are four digits: the first two identify the district, the last two identify the specific port within it. Portland, Maine is 0101, for example.¹ You’ll see Schedule D on both export and import filings whenever a U.S. port needs to be named.

Schedule K identifies foreign seaports in U.S. trade data using five-digit codes. The list is maintained primarily by the Army Corps of Engineers for waterborne commerce statistics, with supplemental codes added by CBP.² It shows up on ocean shipping documents and on CBP filings that ask for a foreign port of lading or unlading.

UN/LOCODE is the international standard. Each code is five characters: a two-letter ISO 3166-1 country code followed by a three-character location identifier. Los Angeles, for instance, is USLAX.³

Each UN/LOCODE entry also carries a function indicator showing what kind of transport location it is. A “1” means seaport, “4” means airport, and “B” means border crossing. Locations with multiple functions get multiple digits, so a city serving as both seaport and airport might carry “1–4—-.”³ Entries marked with status “RQ” are still under review and shouldn’t be used on filings.

Where to Get the Current Lists

Codes change more often than most filers expect. New ports open, administrative boundaries shift, older codes get retired. Pull from the official source every time rather than trusting a third-party database that may lag behind.

Schedule D is published by the U.S. Census Bureau on its Foreign Trade site, sorted both by code number and by port name.¹
Schedule K is available through CBP’s Automated Commercial Environment documentation as Appendix F.²
UN/LOCODE is published by UNECE, with releases cut off on March 31 and September 30 each year. Check whether a newer version has come out since you last looked.

The UN/LOCODE manual flags codes with an “X” when they’re scheduled for removal in the next release and a “+” when they’re newly added. Scanning those change indicators before a filing season saves problems later.³

Which Code Goes on Which Filing

Exports Through AES

Every shipment that requires Electronic Export Information must be filed through the Automated Export System. The port of exportation is a required data element, and it uses the Schedule D code for the physical location where cargo is loaded onto the outbound carrier.⁴

CBP Form 7501 Entry Summary

The 7501 has a dedicated “Port Code” field identifying where the merchandise enters the United States, and this is a Schedule D code.⁵ The port of entry determines which CBP office has jurisdiction and can influence duty rates for certain trade programs. Even when a customs broker prepares the entry, the importer of record carries the “reasonable care” obligation for accuracy of every data element.⁶

Import Security Filing (10+2)

For transit cargo moving through the U.S. under bond, the ISF requires five data elements, one of which is the foreign port of unlading.⁷ Foreign port fields on the ISF draw from Schedule K or UN/LOCODE depending on the specific element.

What a Wrong Code Costs

On the export side, filing false or misleading information under the Foreign Trade Regulations can bring a civil penalty of up to $10,000 per violation.⁸ Knowingly submitting false information through AES can also carry criminal penalties of up to $10,000 and five years of imprisonment.⁹

On the import side, an inaccurate, incomplete, or late ISF can trigger a liquidated damages claim of $5,000 per violation.¹⁰ A wrong port code, a missing element, and a late filing on the same shipment can each draw a separate $5,000 claim.

Fixing a Wrong Port Code

AES Corrections

Correct EEI errors as soon as possible. For predeparture filings, fatal errors flagged by the system must be fixed before the cargo leaves the country. For post-departure filings, fatal errors need correction within five calendar days of the export date. Warning messages from AES must be addressed within four calendar days of the original transmission.¹¹

Entry Summary Corrections

This one catches importers off guard. The port of entry is one of the data elements that cannot be changed through a Post-Summary Correction.¹² If a 7501 goes in with the wrong port code, the standard PSC route is closed. Resolving it means working directly with the port director’s office, which can mean reliquidation or a protest depending on the circumstances. Verify before you file.

Common Mistakes to Avoid

Most port code errors trace back to the same handful of habits: copying a code from an old shipment without checking whether it’s still valid, confusing the port of lading with the port of unlading, or using the wrong code system entirely — a Schedule K code where the form expects Schedule D.

A few practices catch nearly all of these. Bookmark the official sources and check them before each new trade lane; a code that worked last quarter may have changed. Match the code system to the filing: AES and the 7501 use Schedule D for U.S. ports, and the ISF uses Schedule K or UN/LOCODE for foreign ports depending on the field. If a broker handles your filings, spot-check the port codes yourself, because the importer of record still owns the accuracy.⁶

1
U.S. Census Bureau. Schedule D – District and Port Codes and Descriptions
2
U.S. Customs and Border Protection. ACE Appendix F – Schedule K – Foreign Port Codes
3
United Nations Economic Commission for Europe. UN/LOCODE Manual
4
U.S. Census Bureau. AES Participants Data
5
U.S. Customs and Border Protection. CBP Form 7501 Entry Summary
6
U.S. Customs and Border Protection. Tips for New Importers and Exporters
7
U.S. Customs and Border Protection. Import Security Filing – When to Submit to CBP
8
GovInfo. 15 CFR 30.71 – False or Fraudulent Reporting on or Misuse of the AES
9
Office of the Law Revision Counsel. 13 USC 305 – Penalties for Unlawful Export Information Activities
10
U.S. Customs and Border Protection. CBP Dec. 09-26 – Guidelines for the Assessment and Cancellation of Claims for Liquidated Damages
11
eCFR. 15 CFR 30.9 – Transmitting and Correcting Electronic Export Information
12
U.S. Customs and Border Protection. Post Summary Corrections