When returning to the United States from St. Maarten (a popular duty-free port), the standard federal allowance is one liter (33.8 fl. oz.) of alcohol duty-free per person over the age of 21. However, because St. Maarten is part of the Caribbean Basin, you may actually be entitled to a higher exemption of up to two liters, provided that at least one of those liters was produced in a Caribbean Basin Initiative (CBI) country. If you bring back more than your duty-free allowance, you are legally required to declare it and pay a small "Internal Revenue Service" tax and duty on the additional bottles. While there is no strict federal limit on how much alcohol you can bring back for personal use, bringing an "unusual quantity" (like multiple cases) may cause Customs and Border Protection (CBP) to suspect you are importing it for commercial resale, which requires a permit. Additionally, be aware of your home state's laws, as some states ( like Texas or California) have stricter limits on how much alcohol an individual can physically bring across the border regardless of federal duty-free status.