US visa and immigration basics
US immigration law is vast and complex, governed primarily by the Immigration and Nationality Act. This guide gives you a high-level map of the main pathways, how they work, and what to watch out for — so you can ask better questions when you do speak with a professional.
1. Nonimmigrant visas: temporary stays
Nonimmigrant visas are for people coming to the US temporarily for a specific purpose. The most common include: B-1/B-2 for business visitors and tourists (typically up to 6 months), F-1 for academic students, J-1 for exchange visitors, H-1B for workers in specialty occupations (requires a bachelor's degree or equivalent and is subject to an annual cap), L-1 for intracompany transferees, and O-1 for individuals with extraordinary ability. Each category has its own eligibility requirements, application process, and limits on what you can do while you're here.
2. Immigrant visas and green cards
A green card — officially lawful permanent residence — lets you live and work in the US indefinitely. The main pathways are: family sponsorship (a US citizen or permanent resident relative petitions for you), employment-based sponsorship (your employer proves no qualified US worker is available), the Diversity Visa Lottery (random selection from countries with low immigration rates), and refugee or asylum status. Each category has annual numerical limits and per-country caps that create backlogs for nationals of high-demand countries like India, China, Mexico, and the Philippines.
3. Adjustment of status vs consular processing
If you're already in the US and an immigrant visa becomes available, you may be able to adjust your status to permanent resident without leaving the country — if you entered lawfully and haven't violated your status. If you're outside the US, you go through consular processing at a US embassy or consulate in your home country. The two paths involve different forms, timelines, and risks.
4. Common pitfalls and what trips people up
Overstaying a visa by even one day can have serious consequences — including a bar on re-entry of 3 or 10 years depending on how long you stayed unlawfully. Working without authorization or misrepresenting facts on an application can make you permanently inadmissible. Changes in immigration policy can affect processing times and eligibility overnight. Because immigration law is federal and highly technical, mistakes are expensive to fix and sometimes can't be fixed at all.
5. Where to get reliable information
The official source is the US Citizenship and Immigration Services website (uscis.gov), which has forms, fee schedules, and processing-time estimates. The Department of State's website handles visa bulletin updates and consular processing info. Be wary of unofficial websites that charge for free forms or promise results that sound too good to be true. Immigration law changes frequently, so check dates on anything you read.
Common questions
- What's the difference between a visa and a green card?
- A visa is temporary permission tied to a specific purpose. A green card is permanent residence, a path to citizenship.
- What are the main US visa types?
- Nonimmigrant: H-1B (work), F-1 (study), B-1/B-2 (visit). Immigrant: family-sponsored, employment-based, diversity lottery, asylum.
- How long does a family green card take?
- Immediate relatives of US citizens have no cap. Other categories can take years or decades depending on country of origin.
Immigration questions are rarely one-size-fits-all. Tell the assistant your situation — visa type, country, sponsor — for a plain-language starting point.
This guide is general information about US immigration law and is not legal advice. Immigration law is federal, highly technical, and changes frequently. For your specific situation, consult a licensed immigration attorney or an accredited representative recognized by the DOJ.