If you are a traveler passing through the U.S. and the only reason for entering the U.S. is to transit, you need a C-1 transit visa.  Prior to your trip, you and each family member travelling with you have to apply for and obtain individual C-1 visas at a U.S. Embassy/Consulate.  You are required to leave the U.S. on your scheduled departing flight.

If you are a crewmember traveling to the U.S. as a passenger to join a ship/aircraft you will work on, providing services for operation, you need a C-1 transit visa.  You will ALSO NEED a D crewmember visa.  Often, these two visas are issued as a combination C-1/D visa.

If you are a government official passing through the U.S. and the only reason for entering the U.S. is to transit, you need a C-3 transit visa.  Prior to your trip, you and each family member travelling with you have to apply for and obtain individual C-3 visas at a U.S. Embassy/Consulate.  You are required to leave the U.S. on your scheduled departing flight.

If you are a foreign national proceeding in immediate and continuous transit through the U.S. to or from the United Nations Headquarters District, under provisions of the Headquarters agreement with the United Nations, you need a C-2 diplomatic transit visa. Travel within the U.S. will be limited to the immediate New York City vicinity.

How to apply

 Prior to your trip, you have to apply for an appropriate visa at a U.S. Embassy/Consulate.  You must prove the following:

1. You are entering the U.S. only to pass through in transit.

2. You have enough funds to reach your proposed destination.

3. You have a ticket or other means to reach your proposed destination.

4. You have permission (if necessary) to enter the country of your final destination.