Visas, green cards and citizenship: how the system fits together

If you have just arrived in the United States, a few words keep coming up: visa, status, green card, A-number, USCIS. They sound like they mean the same thing, and they do not. This lesson lays out how the pieces fit together, so the letters, forms and conversations ahead of you make sense.

Immigration rules are set by law and they change over time. Only a licensed attorney, or a representative accredited by the Department of Justice, may advise a person about their own case, so nothing here says what anyone qualifies for or what to file.

A visa is permission to ask to enter

USCIS describes a visa as a document that lets the person holding it apply for entry at a port of entry, in a classification such as visitor, student or temporary worker. It does not guarantee admission. Visas are issued abroad by US embassies and consulates, part of the Department of State.

Categories divide into two families. Nonimmigrant categories are temporary: the person is admitted for a specific purpose, for a limited time, with conditions on the stay. Immigrant categories are the ones that lead to permanent residence.

The visa is the travel document used to arrive. Status is the immigration category a person holds while in the country, and status is what shapes daily life.

Permanent residence and citizenship are separate steps

A green card, officially a Permanent Resident Card, means lawful permanent residence, which USCIS says allows a person to live and work permanently in the United States. USCIS publishes the eligibility categories for a green card, and there are several. They include family and employment, and the list also covers refugee or asylee status, special immigrants, victims of human trafficking and crime, victims of abuse, and other categories. The USCIS eligibility categories page is where to see all of them.

USCIS also lists what permanent residence carries. Permanent residents may live and work here as long as they do nothing that makes them removable under immigration law, and they are protected by federal, state and local law. They must obey the law, file income tax returns and report income, and they cannot vote in federal, state or local elections.

Naturalization is the step after that. USCIS defines it as how a person not born here voluntarily becomes a citizen, granted to a lawful permanent resident who meets requirements Congress set in the Immigration and Nationality Act. Citizenship can also come through US citizen parents.

Five agencies, five different jobs

USCIS, part of the Department of Homeland Security, administers immigration benefits for people entitled to stay temporarily or permanently: green cards, employment authorization and naturalization among them. The Department of State runs visa work abroad.

Customs and Border Protection, also part of Homeland Security, works at ports of entry, and CBP says its officers determine admissibility when travelers arrive. Immigration and Customs Enforcement is the enforcement side: arrest, detention and removal.

The Executive Office for Immigration Review sits in the Department of Justice, not in Homeland Security. It runs the immigration courts, and the Board of Immigration Appeals reviews their decisions. It was set up in 1983 to keep those courts separate from the immigration agency.

The A-number, and why status keeps coming back

An A-number, short for Alien Registration Number, is a unique seven, eight or nine digit number that the Department of Homeland Security assigns to a person. USCIS names places where people see it, including the immigrant data summary, the USCIS Immigrant Fee handout, and the visa stamp, where it appears as the Registration Number. Where the number has to be written as nine digits, USCIS says a shorter A-number takes a zero after the A: A12345678 becomes A012345678.

Status is the thread running through the rest of this series. USCIS says the conditions for working, and how long a person may work, depend on the type of immigration status Homeland Security granted, and some people hold an Employment Authorization Document as proof of permission to work. Driver's licenses come from state motor vehicle agencies, so those rules are set state by state.

Where the official answer lives

For applications, permanent residence and naturalization, uscis.gov is the official source. When it is unclear which agency owns a question, usa.gov is the government's own guide and points you to the right one.

USCIS repeats one warning. Only an attorney, or an accredited representative working for an organization recognized by the Department of Justice, can give legal advice on an immigration case. A notario publico is not authorized to provide immigration legal services in the United States, even though notaries are lawyers in some other countries.

What to remember

• A visa lets someone apply to enter. Status is the category they hold once they are here, and status is what matters for daily life.
• Nonimmigrant categories are temporary. Immigrant categories lead to lawful permanent residence, the green card.
• Naturalization is a separate step, with requirements Congress wrote into law.
• USCIS decides applications, the Department of State issues visas abroad, CBP works at ports of entry, ICE enforces, and the immigration courts sit in the Department of Justice.
• Rules change over time, and only a licensed attorney or an accredited representative may advise on a case.