There are limits on the number of U.S. green cards (lawful permanent residence) made available under U.S. immigration laws, at least in certain categories. For many would-be immigrants, this means they must wait for a while after applying—sometimes ten years or more—to become eligible to become a permanent resident.
No limits apply to the number of green cards that can be issued to immediate relatives of U.S. citizens. Immediate relatives include the U.S. citizen’s parents (if the citizen is over age 21), husband or wife, and unmarried children under the age of 21. Similarly, no limits currently apply to the number of people who can gain a green card based on asylee or refugee status.
For people who qualify in most other categories, however, annual quotas limit the number of available green cards. Both family and employment preference-based green cards are affected by these quotas.
Green cards allocated annually to employment-based categories, including investors and "special immigrants," number 140,000 worldwide. Approximately 480,000 green cards worldwide can be issued each year in the family categories.
Only 7% of all worldwide preference visas can be given to persons born in any one country. There are, therefore, two separate quotas: one for each country and one that is worldwide. This produces an odd result, because when you multiply the number of countries in the world by seven (the percentage allowed to each country) you get a total that's much larger than 100.
What this means from a practical standpoint is that the 7% allotment to each country is an allowable maximum, not a guaranteed number. Applicants from a single country that has not used up its 7% green card allotment can still be prevented from getting green cards if the worldwide quota has been exhausted.
As usual, there are currently waiting periods in many preference categories. The waits are especially long for people attempting to immigrate from China, Mexico, India, and the Philippines, due to the high demand from those countries.
In addition to the fixed worldwide totals, 50,000 extra green cards are given each year through the ethnic diversity visa or lottery category. Qualifying countries and the number of green cards available to each country are determined each year according to a formula.
The practical effect of these green card limits is, in some cases, to completely discourage people from applying for a green card. For example, someone who receives a job offer from a U.S. employer, but discovers that in their line of work, the wait for a green card will be ten years, is likely to give up. After all, how many employers will keep a job open for that length of time?
In other cases, the person might decide to sign up for the long wait, if only to see what happens. You can always change your mind. For example, if you have a brother or sister who is a U.S. citizen, he or she could start the immigration process on your behalf (by filing USCIS Form I-130), and then when a green card finally becomes available, you could decide whether you are at a stage in your life where you want to pursue it.
Of course, in the family-based preference categories, maintaining your eligibility can sometimes be a challenge. If, for example, you are trying to immigrate as the unmarried child of a lawful permanent resident, you will need to make sure not to get married until after you have received your U.S. green card.
In some situations, it’s possible to shorten your wait for a U.S. green card. For example, if you are the spouse of a lawful permanent resident, and that person becomes a U.S. citizen, then you become an immediate relative and can proceed with your green card application immediately.
For details on eligibility and further information on how long you might wait for a green card, given the limited numbers, consult with a U.S. immigration lawyer. Or for a summary of the different types of green cards and instructions on handling the immigration application process yourself, see U.S. Immigration Made Easy, by Ilona Bray (Nolo).