U.S. immigration law sorts noncitizens into two broad groups: immigrants, who intend to live in the country permanently through a green card, and nonimmigrants, who are admitted temporarily for a specific purpose such as visiting, studying, or working. Which group a person falls into — and which category within it — shapes what they may do, how long they may stay, and whether any path leads to permanent residence and, eventually, citizenship. Several federal agencies each run a different part of the system.
Status as of July 2026. A long-standing law requires noncitizens who stay 30 days or longer, and who were not already registered through a visa, an I-94 record, or a prior application, to register with USCIS — a duty the government began actively enforcing in April 2025 through the newer Form G-325R. A final rule adopting the requirement took effect on June 29, 2026. Registration is not an immigration status and grants no benefit or work authorization; noncitizens age 18 and older are generally required to carry proof of registration. Enforcement across the system has broadly intensified.
Immigrants and nonimmigrants
The most basic division in the system is between temporary and permanent. A nonimmigrant is admitted for a defined purpose and period — a tourist, a student, a temporary worker — and is expected to leave when that purpose ends; these categories are covered under nonimmigrant visas. An immigrant is someone approved to live in the United States permanently as a lawful permanent resident, the formal name for a green card holder. Permanent residents may live and work anywhere in the country and, after meeting the requirements, may apply for U.S. citizenship. A single person can move between these worlds over time — for example, entering as a student and later becoming a permanent resident.
A visa and a status are not the same thing
Two terms are often confused. A visa is a travel document placed in a passport by a U.S. consulate abroad; it lets the holder travel to a port of entry and ask to be admitted. Status is the legal category a person holds once they are actually admitted into the country, and it is governed by the Department of Homeland Security rather than the consulate. The two can move independently: a visa stamp can expire while a person remains in valid status inside the U.S., and a person's status can end even though the visa in their passport still looks valid. This is why the record of admission — the Form I-94 — often matters more than the visa sticker for someone already in the country.
The main paths to a green card
Most permanent immigration runs through one of four broad routes. Family is the largest: U.S. citizens and permanent residents can petition for certain relatives. Employment covers job-based categories, usually sponsored by an employer. Humanitarian protection covers people fleeing harm or in vulnerable situations — including asylum and refugee status, and programs described under humanitarian protection. The diversity visa lottery offers a limited number of green cards each year to people from countries with low rates of recent immigration. Each route has its own eligibility rules, and many involve long waits governed by annual numerical limits.
Who runs the immigration system
No single agency runs immigration; several divide the work. USCIS (within the Department of Homeland Security) handles applications and petitions — green cards, work permits, naturalization, and registration. CBP, also within DHS, controls the border and ports of entry and decides who is admitted. ICE, the third DHS component, handles interior enforcement, including detention and removal, described under enforcement and detention. The Department of State issues visas at its consulates abroad and publishes the monthly Visa Bulletin. Finally, the immigration courts — run by EOIR within the Department of Justice, not DHS — decide removal cases, covered under immigration court and removal.
Out of status, unlawful presence, and changing status
Being out of status means violating the terms of an admission — for example, working without authorization, staying past the authorized date, or leaving a program of study. Unlawful presence is a related but narrower idea: a specific clock that counts time spent in the country without authorization and that, once it passes 180 days or a year, can trigger bars on returning after departure. A person can be out of status without immediately accruing unlawful presence, and the two are measured differently. Two moves within the system have similar names but different meanings: a change of status switches a person from one nonimmigrant category to another while they remain in the U.S. (a student moving to a work category, for instance), while adjustment of status is the process of applying for a green card from inside the country, on Form I-485, for those who are eligible.
What is the difference between an immigrant and a nonimmigrant?
An immigrant is admitted to live in the United States permanently, as a lawful permanent resident (green card holder), and can later pursue citizenship. A nonimmigrant is admitted temporarily for a specific purpose — such as tourism, study, or a fixed-term job — and is expected to depart when that purpose ends. The category determines what a person may do and how long they may stay.
What is the difference between a visa and status?
A visa is a document issued by a U.S. consulate abroad that allows a person to travel to a port of entry and request admission. Status is the legal category the person holds once admitted, managed by the Department of Homeland Security. A visa can expire while a person keeps valid status in the U.S., and status can lapse even when the visa still appears valid, so the two are tracked separately.
What is the difference between being out of status and unlawful presence?
Out of status means having broken the conditions of an admission, such as overstaying or working without permission. Unlawful presence is a distinct statutory count of time present without authorization, and reaching 180 days or one year of it can create a 3-year or 10-year bar on returning after leaving the country. Someone can be out of status without unlawful presence building at the same rate, so the two concepts do not always line up.
What is a change of status?
A change of status is the process of moving from one nonimmigrant category to another without leaving the United States — for example, a student in F-1 status shifting to a temporary work category. It is requested from USCIS, and the person generally must be maintaining valid status at the time. It is different from adjusting to permanent residence.
What is adjustment of status?
Adjustment of status is the way an eligible person already inside the United States applies to become a lawful permanent resident without returning to their home country for consular processing. It is filed on Form I-485. Eligibility depends on the immigrant category, and, where a category is numerically limited, on a visa being available.
Which agency handles what?
USCIS decides applications and petitions, including green cards, work permits, and naturalization. CBP runs the border and ports of entry and decides admission. ICE handles interior enforcement, detention, and removal. The Department of State issues visas abroad and publishes the Visa Bulletin. The immigration courts, part of EOIR within the Department of Justice, decide removal cases.
Sources we track: USCIS, DHS, EOIR, the Federal Register, and federal courts.