A Harmonized Tariff Schedule is a hierarchical and standardized system of imposing tariffs on imported goods. The Harmonized Tariff Schedule of the United States uses the Harmonized Commodity Description and Coding System established by the World Customs Organization and is updated regularly, most recently in July 2015.
In addition to being standardized in classifying types of goods, the Schedule is harmonized in that it is both exhaustive and hierarchical, unlike prior tariff laws that stood alone. According to United States International Trade Commission, the Harmonized Tariff Schedule replaced all of the previous U.S. tariff schedules in 1989. The Harmonized Tariff Schedule of the United States Annotated, or HTSA, codifies the tariff rates for all of the goods that are imported to the country, based on their Harmonized classifications. The most recent published HTSA is available on the International Trade Commission website.
Even though the International Trade Commission publishes the HTSA, the Bureau of Customs and Border Protection of the Department of Homeland Security must interpret the schedule and enforce its terms. According to Customs and Border Protection, most countries fall into the Normal Trade Relations, or NTR, category with the United States. As of the last update to the NTR list in April 2014, only Cuba and North Korea are not covered by Normal Trade Relations. The tariffs charged on goods from Cuba and North Korea are higher than those imposed on goods from other countries.