Some immigrants who are already in the United States and eligible for permanent residence can apply for, and receive, a green card or lawful permanent residence without leaving the country. They do so through a procedure called "adjustment of status" (AOS). However, the AOS procedure is not open to every immigrant. Some people, depending on their current visa or immigration status, are required by law to leave the United States to attend their green card (immigrant visa) interview at a U.S. embassy or consulate in their home country.
If you are in the United States after having stayed beyond the time permitted under the terms of your visa, then you most likely are not eligible for AOS. This procedure is mainly open to people who are not only eligible for green cards, but who:
As mentioned, a few exceptions exist, which are discussed below.
First, let's make sure you're looking at the right expiration date. It's normally shown not on the visa itself, but on the Form I-94 Arrival/Departure Record that was created for you when you entered the United States.
I-94s were once printed on pieces of paper, and still are at some ports of entry, but most U.S. entrants' I-94 information is now entered into a database by Customs and Border Protection (CBP). You can check for yours on its website.
If you entered the U.S. as an F-1 student, the I-94 will likely say "D/S," for "duration of status," rather than a date. That means you can stay until you've finished your studies, so long as you don't do something to violate your student status.
The expiration date on your original visa, which is the document with which you entered the United States, does not indicate how long you can stay in the United States. It shows only how long you can use that visa for U.S. entry. Again, it's the date on your I-94 that you should be looking at.
If you realize that your permitted stay on your I-94 is about to expire, and you're not quite ready to apply for adjustment of status, and you don't fit into an exception, look into whether you can apply for an extension or renewal of your visa status. That way, you might be able to hang onto your eligibility to adjust status for when the time is right.
Despite the general rule that people whose authorized stays in the U.S. have expired cannot use the adjustment of status procedure to get a green card, there are a few categories of people who might be able to stay in the United States and do just that:
Figuring out whether you fit into one of these exceptions can be difficult, and will depend on more details in your personal situation than we can describe at length here. If you have any questions, you'd be wise to consult an experienced immigration attorney.
If you are in the United States beyond your authorized stay, and haven't yet submitted your adjustment of status application to U.S. Citizenship and Immigration Services (USCIS), and you decide to stay in the United States regardless, you will be taking a huge risk.
Staying past your authorized date without an extension or a pending adjustment of status application on file could be grounds for penalties that will affect your ability to adjust status in the future, or apply for most other sorts of immigration benefit.
If you're caught by U.S. immigration authorities (Immigration and Customs Enforcement, or ICE), your overstay could result in your removal from the United States and a possible ten-year bar on returning. Also, sometimes being arrested by regular police can result in your being turned over to ICE after jail time. (See The Immigration Hold Process After Jail.)
Once you have submitted your AOS application, you will receive a work permit (assuming you included a Form I-765 along with the main form, the I-485) and can legally remain in the United States until a decision is made regarding your green card. At that point, it probably won't matter if your originally permitted stay expires while you wait. (The wait for USCIS to move forward, including scheduling you for biometrics and likely an AOS interview, can be several months long.)
Nevertheless, just in case USCIS denies your adjustment of status application, maintaining your previous immigration status can be a safe bet. But extending your status is possible only in visa categories that allow "dual intent," meaning that it won't matter that you're promising to stay in the U.S. temporarily while simultaneously trying to find a way to stay permanently.
If you are in the United States with an expired I-94 but believe you are eligible for permanent residence, by all means contact an immigration attorney. The attorney can examine the facts of your case and come up with an appropriate strategy. You might find that you will either need to leave the United States and reapply for a new visa for U.S. entry, or can simply apply for an extension of your current stay in the U.S., both of which your lawyer can help you to do.