🔖 This article is part of the Customs Glossary Guide

Shipment Control Number (SCN)

The unique identifier assigned by a carrier to track a shipment through U.S. Customs (ACE).

Type: Data Element System: ACE eManifest

Overview

An example of a Shipment Control Number (SCN) / PAPS Number

A Shipment Control Number (SCN) is a unique alphanumeric code assigned to a specific shipment of goods entering the United States. It serves as the primary reference key in the Automated Commercial Environment (ACE), allowing CBP officers to link physical cargo to electronic data.

In the context of highway freight, the SCN is most commonly referred to as the PAPS Number (Pre-Arrival Processing System). However, an SCN is also used for In-Bond shipments, Section 321s, and empty returns.

The "Link": The SCN is the single most important piece of data for border clearance. The Carrier transmits the SCN in their ACE eManifest, and the Customs Broker transmits the same SCN in their Entry. If the numbers match, the shipment clears. If they differ by even one character, the truck is held for "No Bill on File".

Anatomy of an SCN

A valid Shipment Control Number must follow a strict format defined by CBP:

Structure

Prefix (4 Characters): Must start with the carrier's unique Standard Carrier Alpha Code (SCAC) (e.g., ABCD).
Sequence (Up to 12 Characters): A unique alphanumeric sequence chosen by the carrier (e.g., 12345678).
Total Length: Minimum 4 characters, Maximum 16 characters.

Example: If the carrier's SCAC is "ABCD" and the bill number is "98765", the SCN is ABCD98765.

Uniqueness Rule

CBP regulations require that an SCN must be unique for at least 3 years. Carriers cannot reuse a PAPS number or SCN within a 3-year period. Reusing a number will cause the ACE manifest to be rejected as a "Duplicate Bill".

Usage Scenarios

The SCN is used in various ways depending on the type of release:

Scenario	SCN Application
Standard Release (PAPS)	Scenario: A truck hauls auto parts from Canada to the U.S. Usage: The carrier assigns a PAPS number (SCN) to the shipment. A PAPS Barcode Label is stuck to the invoice. The broker uses this number to clear the goods. The officer scans the barcode to release the truck.
In-Bond Shipment	Scenario: Goods are moving inland to a bonded warehouse (IT) or transiting through the U.S. to Mexico (T&E). Usage: The carrier assigns an SCN to the 7512 in-bond movement. This SCN tracks the liability of the goods until they reach their destination or exit the U.S..
Section 321 (De Minimis)	Scenario: A courier van carries 50 small packages, each worth under $800. Usage: The carrier assigns an SCN to the manifest line item for Section 321 release. No broker entry is required, but the SCN is still needed to report the goods to CBP.
LCL / Consolidation	Scenario: A single trailer contains freight from 10 different shippers. Usage: The carrier must generate 10 unique SCNs (one for each shipment). The driver will present a "Manifest Lead Sheet" listing all 10 SCNs, or individual invoices with 10 separate PAPS barcodes.

Usage in BorderConnect

In BorderConnect, the SCN is automatically generated based on your company settings, but can be customized.

Auto-Generation: When you start a new shipment, BorderConnect prefixes your SCAC and adds the next available sequence number (e.g., SCAC + 00001).
Manual Entry: If a shipper provides a pre-printed label, users can manually type that number into the "Shipment Control Number" field to match the physical paperwork.
Stickers: Users can print compliant PAPS Barcode Labels directly from the software to stick on their documents, ensuring the barcode matches the electronic data exactly.

Official Resources

CBP Guide: ACE Truck Manifest Implementation Guide
Supplies: Order PAPS Barcode Labels (BorderPrint)
Software: BorderConnect ACE eManifest