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1. Immigration is a federal matter
Authority over immigration belongs to the national government. The Constitution gives Congress the power to set a uniform rule of naturalization, and the regulation of who may enter and remain in the country has long been treated as inseparable from federal control over foreign affairs and national sovereignty. The result is that immigration is, in practice, an exclusively federal field: states cannot create their own immigration law, and state rules that try to regulate immigration directly are generally preempted (the preemption framework is explained in our U.S. Legal System Overview).
That federal character runs through everything below. A single governing statute, a single set of federal agencies, a body of federal regulations and guidance, and federal adjudicators and courts decide immigration questions. State law still matters at the edges, because the businesses, jobs, contracts, and assets that immigration cases depend on are usually creatures of state law, but the immigration determination itself is federal.
2. The law: statute, regulations, and guidance
The governing statute is the Immigration and Nationality Act (the INA), codified mainly in Title 8 of the United States Code. Almost every immigration concept, from the visa categories to the grounds that make someone inadmissible or removable, traces back to a section of the INA.
Below the statute sit the regulations. Two sets matter most. The Department of Homeland Security's immigration regulations appear in Title 8 of the Code of Federal Regulations, and the Department of State's visa regulations appear in Title 22. As explained in the U.S. Legal System Overview, a valid regulation carries the force of law, subject to the statute and the Constitution above it.
Below the regulations sits a large and practically essential layer of agency guidance. The two most important sources are the USCIS Policy Manual, which consolidates how U.S. Citizenship and Immigration Services interprets and applies the law, and the Department of State's Foreign Affairs Manual, which guides consular officers abroad. Guidance is invaluable for predicting how a case will be handled, but it does not carry the independent force of law, and a court is not bound by it. One feature is distinctive to immigration: the President holds broad delegated power under INA section 212(f) to suspend or restrict the entry of classes of foreign nationals, which is why presidential proclamations can reshape parts of the system quickly. That power is at the center of several developments discussed in the closing section.
3. The agencies that run the system
No single agency runs immigration. The work is divided, and knowing which agency owns which step is half of understanding any case.
Within the Department of Homeland Security, three components do most of the work. U.S. Citizenship and Immigration Services adjudicates benefits and petitions, the applications that ask for a status or a green card. Customs and Border Protection controls admission at airports, land borders, and other ports of entry, and makes the decision to admit or refuse a traveler who arrives at the border. Immigration and Customs Enforcement handles interior enforcement and represents the government in removal cases.
Outside DHS, three more agencies are central. The Department of State runs the consulates abroad that issue visas, maintains the Foreign Affairs Manual, and publishes the monthly Visa Bulletin that controls when immigrant visa numbers become available. The Department of Labor administers the labor-market protections that many work categories require, including the permanent labor certification process (PERM) and the prevailing-wage and labor condition application steps tied to certain visas. The Department of Justice houses the immigration courts and the Board of Immigration Appeals through its Executive Office for Immigration Review. As the U.S. Legal System Overview notes, these immigration courts are administrative tribunals, not Article III courts.
4. Two distinctions to learn first
Two distinctions clear up most of the confusion in immigration.
The first is nonimmigrant versus immigrant. A nonimmigrant comes to the United States temporarily and for a specific purpose, such as work, study, or business travel, and is expected to maintain that limited purpose. An immigrant is admitted to live in the United States permanently, which is what a green card (lawful permanent residence) confers. The categories, the petitions, and the numerical limits all differ depending on which track a person is on.
The second is visa versus status. A visa is a travel document that a U.S. consulate abroad places in a passport, and it allows the holder to travel to a port of entry and ask to be admitted. Status is the legal condition a person holds once admitted, defined by category and period of stay. The two are not the same: a person can hold valid status in the United States while their visa has expired, and a valid visa does not by itself guarantee admission, because that decision rests with Customs and Border Protection at the border. A related point matters for planning. Some categories permit dual intent, meaning the person may pursue permanent residence without jeopardizing the temporary status (H-1B and L-1 are the classic examples), while others require the applicant to show an intent to depart.
5. Temporary categories for business and work
Most business immigration begins with a nonimmigrant category. The main ones a company encounters are these:
B-1 (business visitors): short visits for meetings, negotiations, and similar activities, not for productive employment.
E-1 and E-2 (treaty traders and treaty investors): available only to nationals of countries that have a qualifying commercial treaty with the United States, for those carrying on substantial trade or directing a real investment. The treaty requirement is the threshold question, as discussed in the treaty section of the U.S. Legal System Overview, and the E-2 investor visa will have its own detailed article.
E-3 (Australian specialty workers) and H-1B1 (Chilean and Singaporean professionals): treaty-based variants of the specialty-occupation idea, limited to the named countries.
TN (USMCA professionals): for Canadian and Mexican citizens in designated professional occupations under the United States-Mexico-Canada Agreement.
H-1B (specialty occupations): for positions that require at least a bachelor's degree in a specific field. The H-1B is subject to an annual numerical cap (65,000, plus 20,000 reserved for holders of U.S. master's or higher degrees), requires a labor condition application certified by the Department of Labor, and is heavily affected by recent changes covered in the closing section. Certain employers, such as universities and nonprofit research organizations, are exempt from the cap.
L-1A and L-1B (intracompany transferees): for managers and executives (L-1A) and employees with specialized knowledge (L-1B) transferring from a related company abroad to a U.S. parent, subsidiary, affiliate, or branch.
O-1 (extraordinary ability): for individuals at the top of their field in the sciences, arts, business, athletics, or other areas.
Students and recent graduates also reach the workforce through F-1 status and its optional practical training (including the STEM extension), which often serves as a bridge to one of the categories above. Each of these categories has its own eligibility rules, evidence, and timing, and the ones most relevant to the firm's clients will be treated in their own articles.
6. Permanent residence through employment
Permanent residence through employment runs on a five-preference system. In broad terms:
EB-1 (priority workers): individuals with extraordinary ability, outstanding professors and researchers, and certain multinational managers and executives.
EB-2 (advanced degree or exceptional ability): professionals holding advanced degrees or individuals of exceptional ability. This category includes the National Interest Waiver, which can allow a qualifying person to self-petition without an employer or a labor certification.
EB-3 (skilled workers and professionals): skilled workers, professionals with bachelor's degrees, and certain other workers.
EB-4 (special immigrants): a set of specific groups defined by statute.
EB-5 (immigrant investors): for those who invest in a new commercial enterprise and create at least ten full-time U.S. jobs. Under the EB-5 Reform and Integrity Act of 2022, the minimum investment is $800,000 in a targeted employment area and $1,050,000 otherwise, with the amounts adjusted for inflation on a periodic basis, and investment may be made directly or through a designated regional center (the Regional Center Program is authorized through September 30, 2027).
Two structural features shape the whole employment-based system. First, most EB-2 and EB-3 cases require permanent labor certification (PERM) from the Department of Labor, in which the employer tests the U.S. labor market and establishes that hiring the foreign worker will not undercut the prevailing wage. EB-1, the National Interest Waiver, and EB-5 do not require it. Second, the law caps employment-based green cards at roughly 140,000 per year and limits any single country to about seven percent of the total. Because demand from a few countries far exceeds those limits, applicants born in heavily oversubscribed countries (notably India and China) can face long waits. A person's place in line is fixed by their priority date, and the Department of State's monthly Visa Bulletin shows which priority dates have reached the front of the line and may proceed.
7. How a case actually moves: petition, then visa or adjustment
Most employment cases follow the same arc. An employer (or, in self-petition categories, the individual) first files a petition with USCIS: Form I-129 for nonimmigrant workers, Form I-140 for most employment-based immigrants, and Form I-526 or I-526E for EB-5 investors. The petition establishes that the job, the qualifications, and the sponsoring entity meet the category's requirements.
Once a petition is approved and, for permanent residence, a visa number is available under the Visa Bulletin, the case finishes on one of two paths. A person abroad goes through consular processing: the Department of State's National Visa Center collects the paperwork, and the applicant attends an interview at a U.S. consulate, which issues the visa. A person already in the United States in a qualifying status may instead use adjustment of status, filing Form I-485 to become a permanent resident without leaving the country. Which path applies depends on where the person is and whether they are eligible to adjust, and the choice has real consequences for timing and travel.
8. How decisions are made and challenged
Immigration decisions come from several different bodies, and the route to challenge a decision depends on which body made it.
USCIS adjudicates petitions and applications. When it denies a case, the options may include an appeal to the Administrative Appeals Office or a motion to reopen or reconsider, depending on the form and the issue. Visa decisions made by consular officers abroad are different: under the doctrine of consular non-reviewability, those decisions are largely insulated from court review. Enforcement and removal run through the immigration courts: an immigration judge within the Executive Office for Immigration Review hears the case, the losing party may appeal to the Board of Immigration Appeals, and only then may the matter reach a federal court through a petition for review filed in the regional U.S. Court of Appeals.
Separately, the rules and policies themselves can be challenged. As the U.S. Legal System Overview explains, agency regulations and policies can be tested in federal court under the Administrative Procedure Act, and courts now decide for themselves what the governing statute means rather than deferring to the agency. Two cautions apply in immigration specifically. Presidential proclamations issued under INA section 212(f) receive broad deference, as the recent H-1B litigation shows. And the remedies available in these challenges narrowed in 2025, when the Supreme Court limited the use of nationwide injunctions in Trump v. CASA, so a court order in one case may not protect everyone.
9. The current landscape (2026)
Immigration is unusually volatile, and 2025 brought some of the largest changes to business immigration in decades. The items below are current to early 2026; because several are the subject of active litigation and ongoing rulemaking, anyone affected should confirm the present state of the law before acting.
The $100,000 H-1B fee. On September 19, 2025, a presidential proclamation (Proclamation 10973, issued under INA section 212(f)) imposed a $100,000 payment as a condition of certain new H-1B petitions, principally those for beneficiaries outside the United States or filed for consular processing. A federal district court in Washington, D.C. upheld the proclamation in December 2025 in Chamber of Commerce of the United States v. U.S. Department of Homeland Security, the plaintiffs appealed, and the appeal was placed on a fast track in the D.C. Circuit; additional challenges by other plaintiffs and a coalition of states remained pending. As of early 2026 the fee remained in effect, but its long-term status depends on the appeals.
A new H-1B selection method. DHS finalized a rule in December 2025 that replaces the random H-1B lottery with a weighted selection process favoring higher-wage positions, giving more selection entries to registrations at higher prevailing-wage levels. The rule took effect on February 27, 2026 and applied to the Fiscal Year 2027 cap season, with registration running in March 2026.
Travel, entry, and screening restrictions. The administration expanded entry restrictions affecting nationals of certain countries in stages, and the Department of State increased visa screening, including review of applicants' social media. Interior enforcement also intensified.
These developments mostly affect the H-1B program and entry rules rather than the underlying statutory categories, but they significantly change cost, timing, and strategy, and they will be addressed in the category-specific articles as they settle.
A practical theme connects this section to the firm's other work. Business immigration cases rest on real businesses: a petitioning employer must be a genuine, qualifying entity, and categories like E-2, L-1, and EB-5 turn on the substance of an enterprise and the source of its funds. That is where immigration meets entity formation and governance (see the Texas Business Law Overview) and tax, including treaty benefits and the consequences of U.S. residency (see the Federal Tax Law Overview). Much of the evidence in an immigration case comes from corporate, contract, payroll, and tax records.
