Immigration law is the body of federal law that decides who may enter the United States, who may stay, who must leave, and who may become a citizen. Congress writes immigration law, federal agencies apply immigration law, and immigration courts decide disputed cases. A nurse in Manila, a software engineer in Bangalore, and a student in Lagos all meet the same statute, even when their routes through the statute differ. This article maps the statute, the agencies, the pathways, the limits, and the court process.
What Is Immigration Law?
Immigration law covers admission, residence, removal, and naturalization for people who are not United States citizens. The field splits into two visa families. An immigrant visa leads to lawful permanent residence, the status shown on a green card. A nonimmigrant visa covers a temporary stay for a defined purpose, such as study, tourism, or a fixed work assignment. Immigration law also sets grounds of inadmissibility, the reasons an applicant can be refused entry, and grounds of deportability, the reasons a person already inside the country can be ordered to leave. Consider a Canadian consultant who flies to Chicago for a two-week project. A short business trip needs no visa under a separate admission rule, yet a full-time job in Chicago would pull the same consultant into the work visa system. Purpose and duration decide the category, and the category decides the paperwork.
Where Immigration Law Comes From: The INA and Its Major Amendments
The Immigration and Nationality Act (INA) of 1952 is the core statute, and Congress has amended the INA in 1965, 1986, 1990, and 1996. The United States Constitution gives Congress power to set a uniform rule of naturalization, and courts read that grant together with federal power over foreign affairs. Congress passed the INA in 1952, gathering scattered statutes into one act, codified at Title 8 of the United States Code. Four later statutes reshaped the INA:
- The 1965 amendments, known as the Hart-Celler Act, abolished the national origins quota system and built the preference system for family and employment cases.
- The Immigration Reform and Control Act of 1986 created penalties for employers who hire workers without authorization and gave legal status to long-term residents who met its terms.
- The Immigration Act of 1990 raised the annual ceilings, built the five employment-based preference categories, and created the Diversity Visa Program.
- The Illegal Immigration Reform and Immigrant Responsibility Act of 1996 expanded enforcement, widened the removal grounds, and created expedited removal at the border.
Regulations sit one level below the statute. Title 8 of the Code of Federal Regulations carries the agency rules that turn INA sections into forms, fees, and filing steps, and United States Citizenship and Immigration Services (USCIS) posts the full INA text on its website.
Federal Power and the Role of the States
The federal government controls admission and removal, and state governments control ordinary daily regulation such as driver licensing, professional licensing, and public schooling. A state cannot issue a visa, admit a visitor, or order a deportation. Federal law governs the border and the status of every noncitizen inside the country. State law still touches immigrant life at many points. Texas decides who receives a Texas driver license, California licenses nurses and contractors, and New York sets tuition rules for its public universities. Courts have struck down state laws that tried to create a state removal system, because a state scheme of that kind conflicts with the federal statute. The practical line runs through purpose: if a state rule decides who may enter or remain, the rule belongs to Congress; if a state rule governs a license, a classroom, or a road, the rule belongs to the state. A farmworker in Florida therefore lives under federal immigration law for status and Florida law for a driver license, a fishing permit, and a child in public school.
The Agencies That Run the System
Six federal bodies divide the daily work of immigration law, and each body owns a distinct stage of a case. The Department of State (DOS) runs the consulates abroad. The Department of Justice holds the immigration courts, and the Department of Labor certifies labor market facts for employer cases. The table below assigns each agency its role.
| Agency | Parent department | Main role under immigration law |
|---|---|---|
| United States Citizenship and Immigration Services (USCIS) | Homeland Security | Decides petitions, green card applications, work permits, and naturalization applications inside the United States |
| Customs and Border Protection (CBP) | Homeland Security | Inspects travelers at ports of entry and patrols the border between ports of entry |
| Immigration and Customs Enforcement (ICE) | Homeland Security | Investigates violations inside the country and prosecutes removal cases in immigration court |
| Department of State (DOS) | None, a cabinet department | Issues immigrant and nonimmigrant visas at embassies and consulates, and runs the Diversity Visa Program |
| Executive Office for Immigration Review (EOIR) | Justice | Runs the immigration courts and the Board of Immigration Appeals, where judges decide removal cases |
| Department of Labor (DOL) | None, a cabinet department | Certifies that a job offer meets wage and recruitment tests in employer-sponsored cases |
One family case can pass through four of the six bodies. A citizen files a petition with USCIS, the file moves to a DOS consulate for the visa interview, a CBP officer admits the arriving relative at the airport, and EOIR never sees the file at all, because no dispute arose. EOIR enters only when the government files a charge or a denied asylum claim reaches a judge.
The Main Pathways Into the United States
Four pathways account for nearly all lawful permanent immigration: family sponsorship, employment sponsorship, humanitarian protection, and the diversity lottery. Each pathway starts from a different fact pattern.
Family Sponsorship
A United States citizen or lawful permanent resident starts a family case by filing a petition that proves the relationship. Spouses, unmarried minor children, and parents of adult citizens count as immediate relatives, and immediate relatives face no annual numerical limit. Adult children, married children, siblings, and the spouses and children of permanent residents wait inside the family preference categories, where annual limits apply. A citizen in Ohio who petitions for a brother in Poland joins the fourth family preference and faces a wait measured in years, while a citizen who petitions for a spouse faces processing time only.
Employment Sponsorship
An employer starts most employment cases, and the Department of Labor certifies the job before USCIS decides the petition. The five employment-based preferences rank priority workers first, then professionals with advanced degrees, skilled workers, special immigrants, and investors. Many employment categories require a permanent labor certification, a DOL finding that the employer tested the labor market and offered the required wage. A hospital in Houston that hires a physical therapist from the Philippines follows that sequence: DOL certification, USCIS petition, then a visa number when the category reaches the applicant.
Humanitarian Protection
Refugee status and asylum protect people who face persecution on account of race, religion, nationality, political opinion, or membership in a particular social group. A refugee applies from outside the United States and arrives with status already granted. An asylum seeker applies after arrival or at a port of entry, either to USCIS in an affirmative filing or to an immigration judge in a defensive filing during removal proceedings. The Refugee Act of 1980 wrote the modern protection framework into the INA. A journalist who fled threats at home and reached Texas can file for asylum within one year of arrival, and the one-year filing deadline is a rule of the statute, subject to narrow exceptions.
The Diversity Visa Lottery
The Diversity Visa Program makes up to 55,000 immigrant visas available each fiscal year to natives of countries with historically low rates of immigration to the United States. The Department of State runs the random selection, and DOS calls the selected people selectees rather than winners, because selection only opens the right to apply. A selectee still passes the same medical, security, and eligibility checks as any other immigrant visa applicant. Countries that sent more than 50,000 immigrants in the prior five years sit out of the program for that cycle.
Visa Preference Categories and Per-Country Limits
Congress caps the preference categories each year, and no single country may take more than 7 percent of the family-sponsored and employment-based preference visas in a fiscal year. The family preference floor stands at 226,000 visas a year, and the employment-based level stands at 140,000 visas a year, plus spillover numbers in some years. Section 202 of the INA sets the 7 percent per-country limit, with a 2 percent limit for dependent areas. Demand from India, China, Mexico, and the Philippines exceeds 7 percent in several categories, so applicants born in those countries wait longer than applicants born elsewhere in the same category. The DOS Visa Bulletin, published monthly, prints the cutoff dates that show which applicants may proceed. A priority date works like a place in line: an applicant moves forward when the bulletin date passes the date the petition entered the system. Two nurses with identical qualifications can wait very different times for one reason only, the country printed on the birth certificate.
How a Typical Case Moves Through the System
A standard case moves through four stages: petition, visa number, final processing, and admission or status adjustment. The sequence runs in a fixed order:
- A sponsor or employer files a petition, and USCIS decides whether the relationship or job qualifies.
- The applicant waits for a visa number, if the category carries an annual limit.
- The applicant completes final processing at a DOS consulate abroad or files for adjustment of status with USCIS while lawfully inside the country.
- A CBP officer admits the applicant at a port of entry, or USCIS grants the adjustment, and permanent residence begins.
Fees, medical exams, and security checks attach to the third stage, and USCIS posts processing times by form and office. A spouse case for a citizen often finishes in a span of months, while a sibling case can run past a decade, and the difference comes from the numerical limits rather than from the merits of either family.
Removal Proceedings Under Section 240
Removal proceedings under section 240 of the INA are the standard court process that decides whether a noncitizen may remain in the United States. A case begins when the Department of Homeland Security issues a Notice to Appear, a charging document that lists the factual allegations and the removability charge. The respondent appears before an immigration judge inside EOIR, first at a short master calendar hearing and later at an individual hearing on the merits. The respondent may hire a lawyer at personal expense, because immigration proceedings are civil rather than criminal and the government provides no free counsel. The judge can grant relief where the statute allows it, such as asylum, cancellation of removal, or adjustment of status, and either side may appeal to the Board of Immigration Appeals. A final order of removal authorizes ICE to carry out the departure. A missed hearing carries a heavy price: the judge may order removal in absentia against a respondent who fails to appear after proper notice.
Naturalization: The End of the Permanent Resident Path
Naturalization is the process that turns a lawful permanent resident into a United States citizen, and most applicants qualify after five years of permanent residence. A resident married to a United States citizen can qualify after three years, if the marriage and the shared residence meet the statutory terms. Every applicant must be at least 18 years old, show good moral character, pass an English test and a civics test, and take the oath of allegiance. USCIS conducts the interview and the ceremony scheduling. A resident who gained status through employment in 2021 can file for naturalization in 2026, five years later, and voting rights, a United States passport, and protection from removal arrive with the oath. Citizenship ends the immigration process for that person, because citizens stand outside the admission and removal system.
How Immigration Law Changes
Immigration law changes through four channels: a new statute from Congress, a regulation from an agency, an executive action from the President, or a ruling from a federal court. Only Congress can rewrite the INA itself, raise a numerical cap, or create a new visa category. Agencies write regulations that fill in filing mechanics, and federal law requires public notice and a comment period for most rules. Presidents set enforcement priorities and run programs that rest on existing statutory authority. Federal courts strike down rules that exceed the statute and settle disputes over what INA language means. The Diversity Visa Program shows the channels at work in 2026: the State Department altered the entry process for the DV-2027 cycle and delayed the registration announcement, and a federal court then ordered the department to publish dates and open registration on a set timetable. The statute never moved. The 55,000 figure stayed fixed while procedure and timing shifted around the fixed figure.
FAQs
Who writes immigration law in the United States?
Congress writes immigration law. The Immigration and Nationality Act of 1952 is the core statute, and federal agencies apply the statute through regulations, forms, and decisions.
Is immigration law the same in every state?
Yes. Immigration law is federal, so admission, residence, and removal rules match in all 50 states. States still control driver licenses, professional licenses, and public school rules.
How many diversity visas are available each year?
Up to 55,000. The Department of State runs the Diversity Visa Program for natives of countries with historically low immigration rates, and selection only opens the right to apply.
What does the 7 percent per-country limit mean?
The limit caps each country at 7 percent of the family-sponsored and employment-based preference visas in a fiscal year. High-demand countries form longer queues inside the same categories.
Can a state deport someone or issue a visa?
No. Only the federal government admits visitors, issues visas, and orders removal. State officers act under state law, and courts block state schemes that copy the federal removal system.
What starts a removal case in immigration court?
A Notice to Appear starts the case. The charging document lists the allegations and the charge, and an immigration judge decides the case under section 240 of the INA.
When can a green card holder apply for citizenship?
After five years of permanent residence for most applicants, or three years for a resident married to a United States citizen. Applicants must pass English and civics tests.
Conclusion
Immigration law looks scattered from the outside, yet one statute holds the structure. The INA of 1952, amended in 1965, 1986, 1990, and 1996, assigns the pathways, the caps, and the court process. Six agencies run the machinery, and the 7 percent per-country limit explains most long waits. A reader who can name the pathway, the agency, and the stage of a case can read almost any immigration headline in 2026 and place the story on the map.
