Question: I have my green card. Can I live outside of the U.S. for longer than two years?
Answer: If you are a green card holder who stays outside for less than six months, you only need to show your green card to re-enter the U.S. If you want to stay outside for up to two years, file for a re-entry permit before leaving the U.S. You can only obtain one re-entry permit and cannot extend it beyond two years.
Keep in mind that obtaining a re-entry permit does not preserve residence for when you file for citizenship.
If you cannot return within two years, you can file for a Returning Resident (SB1) visa at the consulate. To obtain the visa, you must be able to prove that you could not return due to circumstances beyond your control. File at least 90 days before you plan to return to the U.S.