The Most Ignored (and Important) Pages in the HTSUS

Section and Chapter Notes: Where the Real Classification Rules Live

Most importers know what an HTS code looks like. Fewer know what it means. And almost no one reads the part that tells you how it should be interpreted in the first place.

Welcome to the Section and Chapter Notes.

These aren’t filler pages or boilerplate disclaimers. They’re legally binding text that determines how tariff headings and subheadings should be applied. In other words, they don’t just support classification, they govern it.

And yet, they’re skipped more often than terms and conditions on a software update.

Where the Real Rules Are Written

The Harmonized Tariff Schedule of the United States (HTSUS) is divided into 22 sections and 99 chapters (with a conspicuous gap at Chapter 77). Each section groups similar products (like base metals, plastics, or textiles), and each chapter further narrows the scope.

Tucked at the beginning of every section and chapter are Notes. These aren’t suggestions. They’re the fine print that determines what belongs and what doesn’t.

For example:

Say you’re importing a composite product. It’s part plastic, part metal, part mystery. The product description might feel like a match for several codes. But the Chapter Notes will often tell you which material governs classification, or whether the item is even covered in that chapter at all.

Skip the Notes, and you’re rolling the dice with CBP.

The Notes Are Binding. Your Broker’s Shortcut Isn’t.

We’ve reviewed countless classifications where everything looked fine until we read the Notes. 

A plastic case classified under a heading for “other articles of plastic,” when the Chapter Note clearly excluded finished cases with hardware. Or a motor entered under Chapter 85 when the Section Note routed it to Chapter 84 due to its function. On paper, it looked defensible. In context, it was wrong.

When these entries are challenged, it’s not the product description or the catalog cut sheet that CBP reaches for. It’s the Section and Chapter Notes. If your classification doesn’t hold up against those, it doesn’t hold up at all.

You Can’t Interpret a Heading Without Its Notes

Here’s the reality: tariff codes aren’t self-contained. The descriptions in the headings can be vague, broad, or deceptively simple. Without the Notes, they’re open to misreading and misclassification.

For example, Chapter 90 covers precision instruments, but Chapter Note 1 carves out everything from basic tools to certain medical devices. Section XVI (covering Chapters 84 and 85) has Notes that redirect multifunction machines based on which function gives the product its essential character. These distinctions matter, and they often make the difference between a 2% duty rate and a 25% one.

So Why Doesn’t Anyone Read Them?

Because they’re dry. Because they’re dense. Because no one ever told most importers (or their brokers) that they’re mandatory reading. But skipping them doesn’t exempt you from them. CBP doesn’t offer partial credit for creative interpretation.

And unlike product specs or invoices, the Notes don’t change just because your marketing team rewrote the description. They’re a fixed point of law and they apply whether you’ve read them or not.

Make the Notes Your Starting Point, Not Your Emergency Exit

Classification errors aren’t always about recklessness. More often, they come from using incomplete sources. If your classification process doesn’t include a review of the relevant Section and Chapter Notes, it’s not a process, it’s a placeholder.

At O’Meara & Associates, we’ve helped clients avoid six-figure duty bills and painful audits simply by reading the parts most people ignore.

Need a second opinion on your classifications – or want help building a defensible strategy from the ground up?

Contact O’Meara & Associates today. We read the fine print so you don’t have to lose sleep over it.