A United States Permanent Resident Card, also known as a green card, is an identification card attesting to the permanent resident status of an alien in the United States of America. Green card also refers to an immigration process of becoming a permanent resident. The green card serves as proof that its holder, a Lawful Permanent Resident (LPR), has been officially granted immigration benefits, which include permission to reside and take employment in the USA. The holder must maintain permanent resident status, and can be removed from the US if certain conditions of this status are not met.

Green cards were formerly issued by the Immigration and Naturalization Service (INS). That agency has been absorbed into and replaced by the Bureau of Citizenship and Immigration Services (BCIS), part of the Department of Homeland Security (DHS). Shortly after re-organization BCIS was re-named to U.S. Citizenship and Immigration Services (USCIS).

An alien with a green card application can obtain two important permits while the case is pending. The first is a temporary work permit known as the Employment Authorization Document (EAD), which allows the alien to take employment in the United States. The second is a temporary travel document, advance parole, which allows the alien to re-enter the United States. Both permits confer benefits that are independent of any existing status granted to the alien. For example, the alien might already have permission to work in the United States under an H1-B visa.

Types of immigration
U.S. immigration legislation in the Immigration and Nationality Act (INA) stipulates that an alien may obtain permanent resident status only through the course of the following proceedings:

immigration through a family member

immigration through employment

immigration through investment

immigration through the Diversity Lottery

immigration through “The Registry” provisions of the Immigration and Nationality Act

Application process for family-sponsored visa
Green card holders and nuclear families
Green card holders married to non-U.S. citizens are unable to legally bring their spouses (or families) to join them in the USA. The foreign spouse of a green card holder must wait for approval of an ‘immigrant visa’ from the State Department before entering the United States. Due to a backlog in processing, such visas can take up to five years to be approved. In the interim, due to immigration intent, the spouse cannot enter the United States on any other visas not even as a visitor. This puts LPRs in a uniquely disadvantaged situation:

visitors and non-immigrants coming to the USA on temporary visas for work, business, or study (including H1, L1, B, and F1 visas) can sponsor their dependent spouses to travel with them;

U.S. citizens can sponsor their spouses to come to the USA in non-immigrant status; the spouse can then convert to an immigrant status under the Legal Immigration and Family Equity Act of 2000 (the “LIFE Act”).