If you stay in the United States past the permitted date according to your visa (shown on your Form I-94 Arrival/Departure Record), you risk being removed from the Unites States (deported) at any time. Nevertheless, many people opt to do this, hoping they will eventually be able to adjust status. (Adjustment of status is the process of applying for a green card without leaving the United States.) Unfortunately, the visa overstay could ruin some of their chances to adjust status.
If you have no current known basis for a U.S. green card, then overstaying your visa in hopes that you will become eligible is a gamble. And even if you become green card eligible, your overstay may interfere with your ability to adjust status, as discussed next.
If you are in fact eligible for a green card -- perhaps because you're closely related to a U.S. citizen or permanent resident, or have an employer willing to petition for you -- that's great. But realize that not everyone who is eligible for a green card is also eligible to adjust status. Most people -- though not all -- will have to return to their home country for the final part of the green card application process, which includes an interview with a U.S. government official.
That might not sound bad, until you realize something important about the grounds of inadmissibility in the U.S. immigration laws. If you stayed in the U.S. unlawfully for more than six months (180 days), when you get to your visa interview overseas they will (unless you fit into some narrow exceptions) penalize you by refusing to allow you back into the United States for three years. If you overstayed for a whole year or more, the penalty is ten years. Your only hope may be to apply for a "waiver" (legal forgiveness) based on hardship to your U.S. citizen or permanent resident relatives, but these waivers can be hard to get.
People who adjust status -- that is, process their whole green card application without leaving the United States -- do not face these penalties.
A few people can adjust status even after their visa has expired, such as those who:
But you shouldn't attempt to figure out your own eligibility to adjust status after an overstay without experienced legal help.
If your visa status is likely to expire before you can apply for adjustment of status, contact an attorney right away, before the visa overstay occurs, to find out whether a renewal is possible in your visa category, or whether there's some other solution to the situation. Keep in mind, it may not be possible to remain legally in the country.
If you have already submitted your Form I-485 and supporting forms and documents to USCIS, and received acknowledgment that it has received and accepted it for processing, you don't have to worry about renewing your visa. Your status in the U.S. is legal while you wait for the interview at which your adjustment of status will be decided upon.
If you overstay a visa and then leave the United States, your record may be examined any time you apply for future visas. You may be denied based on your past history of late departures from the United States.
If you believe you may be eligible for a green card, but are nearing the expiration date on your permitted visa stay, or have already overstayed, you'll definitely want to consult with an attorney. The attorney can analyze your personal situation and tell you how long it's safe for you to remain in the United States, whether you can adjust status, and if not, whether you're likely to qualify for a waiver allowing you to get a green card through processing overseas (known as "consular processing").