1. What are the requirements for re-entry into the United States as an US citizen with a passport?

  2. Are you required to show proof of leaving the US, to begin with? If so what will happen if you lost or don't have any proof of leaving the US?

  3. Are there differences between air entry vs land entry?

  • 1
    Have you considered that some US citizens are born outside the US?
    – phoog
    Commented Aug 13, 2018 at 23:58

2 Answers 2


No. There is not such requirement because the U.S. is among a handful of countries that does not have exit immigration. Although they do get some data, it is not complete and therefore proof of exit may not exist in some cases.

This is particularly the case with land borders. I have crossed the US-Canada and US-Mexico borders several times. When crossing into Canada, you go directly to Canadian immigration. They share some data with U.S. immigration but not with the person crossing, so you would not get proof of exist. Going to Mexico, you may not even go through Mexican immigration, only cross the yellow line delimiting the US and Mexico. When I crossed the border at Tijuana, there was only an official standing there that said Welcome to Mexico and that was it. No passport checks, let alone an exist stamp.

  1. The requirement for a US citizen entering the United States is to present a US passport. This passport establishes your citizenship, and the immigration department is required to admit US citizens if they can prove their citizenship. (There are some exceptions, see Western Hemisphere Travel Initiative.)

  2. US citizens are not required to show proof of leaving. A US citizen may leave the US at any time without telling anybody.

  3. There are some differences between air and land entry, see the WHTI link above.

  • ... and in any case, the fact that the citizen is now seeking entry is incontrovertible proof, should one be desired, that they must have left at some point (unless the passport they present was issued abroad). Commented Aug 13, 2018 at 23:52
  • 1
    There are no "exceptions". If a US citizens manages to arrive at a US port of entry and can prove their US citizenship, they must be admitted, with or without a passport or any other specific document. However, if they are arriving by carrier (airplane or boat), that carrier is supposed to deny them boarding if they don't have the proper documents.
    – user102008
    Commented Aug 14, 2018 at 15:19
  • @user102008: I meant there are exceptions to requiring a passport. Presenting a document other than a passport to establish citizenship is an exception. Commented Aug 14, 2018 at 18:40
  • Nit: unless you the US citizen are charged with a crime; then the court will usually prohibit you from traveling outside its district, much less the country. And the same usually if you are on probation or parole after conviction. Commented Aug 14, 2018 at 22:17

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .