Reentry Permit
Being a Permanent Resident of the U.S. you can travel without restraint outside of the U.S. To reenter the U.S., you need to present your green card from your country of citizenship for readmission if the trip duration is less than one year. You do not need to present the passport to enter the U.S. If the trip duration is greater than one year, but less than two years then a reentry permit is also needed to enter the U.S. A reentry permit is also issued to Lawful Permanent Residents who want to travel outside the U.S., but cannot get a national passport from their country of nationality. Traveling outside the U.S. without a reentry permit could have severe consequences to permanent or conditional residents. It could be determined that you abandoned your resident status. The benefit of having a valid reentry permit is that you do not have to obtain a returning resident visa from a U.S. embassy or consulate. However, the permit does not relieve you of any of the requirements of the U.S. immigration laws. Mere possession of reentry permit does not guarantee admission into the U.S. as you are still subject to immigration inspection at the port of entry to determine admissibility into the U.S. You also may be subject to "secondary inspection" where you will be taken into a separate room and asked questions.

If you intend to travel or live outside the U.S. for more than 5 months in a year, it is advisable to get a visitor visa instead of getting a green card because you may lose the green card based on the assumption of abandonment of intention.

Permanent residents must be physically present in the U.S. when filing the application.

Leaving the U.S. before a decision has been decided does not affect the application. However, if biometric (fingerprint) collection is required, and you depart the U.S. before the collection, your application may be denied.

You may request your reentry permit to be sent to a U.S. embassy or consulate or Department of Homeland Security (DHS) office abroad when you file the application. There is a place on the Form I-131 to furnish the information necessary to receive the re-entry permit outside of the U.S.