Where do you clear customs when flying back from Nicaragua to Canada via the US?

When flying back to Canada from Nicaragua via the US, you will clear customs in the US at your first point of entry. This typically occurs at the airport where you land in the US before your connecting flight to Canada. You will go through U.S. Customs and Border Protection, where you will present your passport and any required documents. After clearing customs in the US, you can continue on to Canada, where you will go through Canadian customs upon arrival.