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Most people who come to the United States temporarily — to work, train, study, or visit — need permission from the U.S. government before they travel. This section explains how that system works and helps you find the category that fits your situation.
A visa is not permission to stay. A visa is placed in your passport by a U.S. consulate abroad, and it only lets you ask to be admitted at a U.S. port of entry. A Customs and Border Protection officer makes the actual admission decision and sets how long you may remain. That period is recorded on your electronic Form I-94, not on your visa. Your visa can expire while you are lawfully in the country, and your permitted stay can end long before your visa does. Always check your I-94.
“Nonimmigrant” means temporary. Each category comes with its own rules about what you may do, how long you may stay, whether your family can join you, and whether they can work. Doing something your category does not allow — most commonly working — can end your status and affect future applications.
Many work categories require an approved petition before you can apply for the visa. For most employment-based categories, a U.S. employer files a petition with USCIS on your behalf, and some also require a filing with the Department of Labor first. Only after approval can you apply for the visa. Building that sequence into your timeline is usually the difference between a smooth process and a missed start date.
Some travelers can enter without one:
A note on Mexico: Mexican citizens are not in a visa-free category. Most travel on a B-1/B-2 visa or a Border Crossing Card, which is itself a B-1/B-2 visa issued as a card.
If none of the above applies to you, you will need a visa.
Common Work Visas — the categories used most often for employment and training, including specialty occupation workers, intracompany transferees, treaty traders and investors, people of extraordinary ability, and professionals under the USMCA.
Student Visas — academic and vocational study. Includes the school’s role in issuing your certificate of eligibility and the rules on working while enrolled.
Exchange Visitors (J-1) — research scholars, professors, trainees, interns, au pairs, camp counselors, and physicians, plus the two-year home residency requirement that applies to some J-1 holders.
Visitor Visas — short business trips, tourism, and medical treatment.
Extension of Stay — how to ask for more time before your authorized stay runs out, and why filing early matters.
List of Temporary Visas and Classifications — the full A-to-Z reference if you are not sure where you fit, or if your situation is unusual.
Consular processing has become more demanding, and timing has become harder to predict. Applicants are now generally expected to interview in their country of nationality or residence. Online presence and social media review now applies to a wide and growing list of categories, and applicants in those categories are told to make their profiles publicly visible. A pilot program requires visitor visa applicants from certain countries to post a refundable bond of several thousand dollars. Entry restrictions under presidential proclamation currently affect nationals of a substantial number of countries, in some cases fully and in others only for particular visa types.
Because these requirements, the fee schedule, and the affected country lists change frequently, we do not reproduce them here. Verify current requirements on travel.state.gov and uscis.gov, or ask us before you book travel or commit to a start date.
Choosing the right category, sequencing the petition and the visa application, and avoiding a status gap are where most problems are made — and where they are cheapest to prevent. If you would like help thinking through your options, contact our office.
This page is general information, not legal advice, and does not create an attorney-client relationship. Immigration law changes often. Last reviewed: July 31, 2026.