An immigrant to the United States who has been granted the right to live and work in the U.S. permanently receives a "green card," more formally known as a permanent resident card. But no one receives it right away. In fact, delays in the process, whether they come from the slow grinding of the immigration bureaucracy or built-in issues like numerical limits on the annual supply of visas, are a source of complaint for many immigrants.
Of course, not everyone has the same experience with the application process. That's partly because there are numerous legal bases upon which one can become a permanent resident and receive a green card, and a number of procedural methods by which to do so. The most likely grounds for eligibility include having either an employer or a family member who is a U.S. citizen or permanent resident file a petition for you. Winners of the diversity visa lottery can also apply for green cards. Another major way is be granted asylum in the United States.
For most applicants, there are two to four major steps toward receiving a green card, as described here.
Before an employer can so much as contact the U.S. immigration bureaucracy about the possibility of getting a green card for a foreign worker, the employer must conduct an advertising and recruitment process that results in failure to find a U.S. worker who is qualified, willing, and available to take the position. If there is a suitable U.S. worker, that person must get first priority for the job.
Then, the employer must submit a labor certification request to the U.S. Department of Labor, on Form ETA 9089 and wait for it to be approved. This is a process known as "PERM."
Your employer or relative must start the process of communicating with the immigration decision makers by filing a petition on your behalf, using Form I-140 (by employers), I-130 (by family members), or I-129F (by U.S. citizen fiancés).
Other common ways of getting a green card require starting the process by yourself, for example if you are a refugee or seeking asylum within the United States (both of which can eventually lead to getting a green card), you are an investor willing to put a large sum into a U.S. business that you'll be actively involved in (in which case you'd start by filing your own petition on USCIS Form I-526), you are the spouse of a U.S. citizen who is abusive and isn't cooperating with helping you obtain a green card (in which case you'd start by filing your own petition on Form I-360), and so forth.
After submitting the initial petition, you can expect a wait of several months before you get an answer. U.S. Citizenship and Immigration Services (USCIS) gets really backed up at times; you can look at its average processing times for various applications online.
If you're in a category where visas are subject to annual limits, you'll have to wait until your "Priority Date" (which comes from the date your I-130 petition was first received by USCIS) comes up on a waiting list. This can take years, depending on your category and which country you're from. Spouses and unmarried children of permanent residents, for example, often wait around two years. Brothers and sisters of U.S. citizens tend to wait the longest, upwards of 20 years.
Check the State Department's Visa Bulletin for a list of the Priority Dates just becoming current. If you count the length of time between the current Priority Date in your category and today's date, you'll get a rough idea of how long people like you usually wait between I-130 approval and visa availability (though this can, of course, change year by year, depending on how many people apply in the various categories).
At last, you can actually submit the application for a green card. This too is likely to take several weeks or months, depending on where you apply.
The process starts when you either submit your green card application, to a USCIS office (if you're allowed to "adjust status" in the U.S., which not everyone is) or to a U.S. consulate in your home country.
Then you wait for several weeks or months to be called in for an interview. (In the U.S., you'll be asked to attend a biometrics appointment first, at which time your fingerprints will be taken.)
Your local consulate might be able to tell you its average wait time for an interview. For adjustment of status interviews (in the U.S.), check USCIS's Check Case Processing Times web page.
At the interview, your visa or green card should be approved (or denied). However, sometimes you won't receive an answer that day, because security checks on you have not been completed, or the immigration authorities want you to supply more documents or information first.
Another common hitch in the application process is when an applicant appears to be "inadmissible" to the U.S., for criminal, security, health, or public charge reasons. In some cases, you might be given time to supply additional evidence that you are not inadmissible, or to apply for a waiver (legal forgiveness).
Hiring an experienced immigration attorney can help you to make sure things move as swiftly as possible and that there are no unexpected hitches along the way. The attorney might suggest strategies to make sure nothing goes wrong during the long wait, such as having more than one person file petition for you (if, for example, you have a U.S. citizen brother as well as a spouse), thus giving you a backup if one petitioner dies or if you divorce.