If you have become close to an undocumented immigrant (sometimes called an illegal alien) living in the United States, and that person doesn't seem to have any realistic hope of legalizing his or her status, you wouldn’t be the first to ask whether adoption will help that person gain U.S. lawful permanent residence or a green card. Unfortunately, in order to make that work, all the following would have to be true:
The law is cut and dried on this point. For immigration purposes, an adoption must be finalized before the child turns 16 years of age. And because adoption itself can be a lengthy process, you’re probably better off starting when the child is age 15 or younger.
An adoption after the age of 16 may benefit the person in ways unrelated to immigration. For example, it may simplify receiving an inheritance from your estate. But it will not likely help the person get a green card.
In order for an adopted child to receive a green card, the parent must have had legal and physical custody of the child for at least two years while the child was a minor (under 18), and the child must have lived with the adopting parents for at least two years before they file the required initial visa petition with U.S. Citizenship and Immigration Services (USCIS).
You can, in fact, petition a U.S. court for legal custody of the child regardless of his or her legal status, making you the rightful parent. Realize, however, that your legal custody won’t legalize the child’s U.S. stay for immigration purposes. A child who is staying in the U.S. without a visa or other permission from the immigration authorities can still be arrested by the immigration authorities and removed (deported).
Realistically, the immigration authorities would rarely deport an adopted child unless the child had committed a serious crime. Nevertheless, the safest way to go about this process would be to live with the child in another country for the two years. This is impractical for most parents.
In theory, a U.S. lawful permanent resident has the right to petition for an adopted child to receive U.S. residence. In practice, however, the residency requirements make this virtually impossible (unless they adopted and lived with the child before coming to the U.S.). The problem is the potential need to live overseas with the child. Such a long absence may result in the permanent resident parents' green card being canceled as "abandoned."
Assuming you make it this far, including obtaining legal custody of the child and getting through two years legal physical custody, what happens next depends on whether the child entered the U.S. with or without inspection.
If the child entered the U.S. without inspection. If the child entered without inspection, perhaps by crossing the border with the help of a coyote or smuggler, then at the end of the two years of legal custody and having the child live with you, you can file a visa petition with U.S. Citizenship and Immigration Services. Once that is approved, the case will be transferred to a U.S. consulate abroad. You will have to take the child to the U.S. consulate for the visa interview (which completes the green card application process).
One bit of good news: A child under 18 can’t rack up "unlawful presence" in the U.S., and therefore you probably won’t have to worry about the three- and ten-year bars being used to block the child from returning to the United States.
If the child entered the U.S. legally but has overstayed. If the child originally came to the U.S. on a visa, but stayed past the expiration date on his or her Form I-94 Arrival/Departure Record, you can file a visa petition and an adjustment of status application (both at the same time) with USCIS.
Adopting an undocumented immigrant is a highly complicated process, and you’ll probably want to get an immigration lawyer’s help. If the child is an orphan, you may have another alternatives that we didn’t discuss here, namely to process the immigration papers required for an orphan child.
The adopted child - assuming the green card petition is successful - will be able to eventually become a U.S. citizen. See How Foreign-Born Adopted Children Get U.S. Citizenship.