Upon inspection, the Customs and Border Protection (CBP) officer will ask for several documents, these are:

• Northwestern issued I-20 or DS-2019;
• A valid passport (valid six-months into the future);
• A valid F-1 or J-1 visa stamp (placed inside the passport at the consulate or embassy abroad);

These documents should be kept with the traveler at all times. Be prepared to present these documents to CBP upon arrival (this will happen before you have access to your checked luggage, so please plan acccordingly).

It is very important that this entry is recorded correctly and you may need to confirm with the CBP officer entrance in F-1 or J-1 student status. A few points to keep in mind:

• The entry stamp should indicate a written "F-1" or "J-1" depicting the recorded entry status.
• The entry stamp should also note "D/S," which stands for "Duration of Status."

Duration of Status (D/S) indicates you have been admitted to the U.S. in F-1 or J-1 status for the duration of your academic program. This period of time is indicated on the I-20 and DS-2019. If you are not provided a "D/S" on entry, ask the CBP officer for clarification.

See Department of Homeland Security's website for more information: "Arriving at a U.S. Port of Entry ... What a Student Can Expect" 

See here for more information about the updated electronic I-94 process