At U.S. customs, you generally must declare anything you bought, received as a gift, or are bringing in that could be restricted or dutiable —especially food, alcohol, tobacco, currency over $10,000, and medications/pharmaceuticals. U.S. Customs and Border Protection also says travelers should declare all items purchased abroad, including duty-free items, and be ready to itemize them if asked.

Usually declare

  • Food and agricultural products.
  • Alcohol and tobacco.
  • Cash or monetary instruments over $10,000.
  • Medications, especially controlled substances or anything not in original labeled packaging.
  • Goods bought abroad, even small souvenirs or gifts, if they were acquired on the trip.

Practical rule

If you are unsure, declare it. Declaring something does not automatically mean you will pay duty; it just tells customs what you have and helps avoid penalties for not reporting it.

Simple example

If you return with souvenirs, duty-free alcohol, snacks, and prescription medicine, you should report those items rather than assume they are exempt.

If you want, I can also turn this into a very short customs checklist for air travel.