United States customary units are the system of measurements that are used in the United States. They help us to measure things like length, weight, and volume. It's like a bigger version of the measuring system we use in our kitchens, which includes things like teaspoons, tablespoons, cups, pints, quarts, gallons, and ounces. In the United States customary units system, we use things like inches, feet, pounds, and gallons to measure length, weight, and volume. These measurements tell us how big or heavy something is, or how much of a liquid it can hold.