Immigrant and Non-immigrant Categories
This is a list of the immigrant and non-immigrant categories for entry to the US.
An immigrant category means something that gives you lawful permanent resident (LPR) status;
A non-immigrant category means a temporary status that allows you to engage in a specific activity, usually for a fixed period of time.
First of all some basics - typically, but by no means always, you require a visa to enter in a non-immigrant category. This is why they're called: "categories" rather than: "visas". Also understand a visa is merely an entry document; for example you could enter with a visa for one category and then change status to another category while in the US.
Canadian citizens and belongers of Bermuda are typically exempt from the requirement for a visa, because CBP has direct access to the Canadian Police Information Centre and thus a visa is not needed - however, you still need the relevant USCIS paperwork for that particular category, you just don't need a visa in your passport. Canadians do however require non-immigrant visas for a handful of categories, i.e. A, E, G, K, NATO, S and V.
The reason behind the lettering system is that most non-immigrant categories are based on 8 USC 1101(a)(15) and are a subsection, e.g. the law relating to a B-1 visitor is 8 USC 1101(a)(15)(b).
In this list, the categories most commonly used by people coming from developed countries are listed in bold text.
And another tidbit of information, most, but not all non-immigrant categories are what is known as: "dual-intent", which means you can enter as a non-immigrant, but with the intention to become an immigrant later on.
- A-1, A-2 and A-3 Foreign government officials, their dependents and their servants (no kidding, that's A-3);
- B-1 - visitor for business. Visitors for business can actually do quite a lot, for example tour guides, installations of equipment, training of staff, giving presentations and so on but typically it is associated with attending a business meeting. Typically you're admitted for six months in this category and can apply for a six-month extension on I-539. (Canadians usually don't need to bother as they don't get an I-94). Canadians and Mexicans enter as B-1 NAFTA and can perform any task listed in 8 CFR 214.2(b)(4)(i). Note that if you're from a visa waiver country, you won't enter as B-1 unless you got a visa - you'll enter as VWB.
- B-2 - visitor for pleasure. Admitted for six months initially (unless you're Canadian or Bermudan as you don't get an I-94). Visitors for pleasure can engage in short-term courses of study (e.g. cookery course). Co-habiting partners of people in other non-immigrant categories also enter as B-2, CBP are authorized to allow admission for one year (so be sure to ask at the POE, otherwise they'll make it six months).
- C-1, C-2, C-3, C-4 - alien in transit, various different categories;
- CFA/FSM, CFA/RMI, CFA/PAL - citizens of Micronesia, the Marshall Islands or Palau are authorized to live and work in the US indefinitely under the relevant Compact of Free Association but remain in a non-immigrant category;
- CW-1, CW-2 - CNMI transitional worker, somewhat similar to H-2B but for certain occupations only and only in the CNMI. CW-2 is for dependents;
- D-1, D-2 - crew member of vessel, (ship, aircraft, etc.) commonly used by airline crew. It is theoretically possible for crew members of ships to get work authorization in the US for longshore work, the employer has to attest to the fact there are not enough Americans available to do the work (in practice, very hard to get);
- C/D - combined C and D, this is commonly used by crew on board cruise ships. Be very careful about this category - the IRS counts the days you spend in US waters for tax purposes;
- DA - Deferred Action. Assigned administratively usually by ICE for whatever reason was deemed appropriate. For whatever reason they've decided it is not in the public interest to put you in removal proceedings, e.g. you're a victim of crime, it would expose your family to severe hardship, etc.;
- DACA - Deferred Action for Childhood Arrivals. This is the program Obama implemented by executive action, applies deferred action administratively across a broad class of people who arrived in the US illegally as minors. Applied for on I-821D, valid for two years;
- DAPA - Deferred Action for Parental Arrivals. An expansion of DACA to the parents of the children, essentially. So broad that Texas and other States sued and got an injunction, arguing it violated the will of Congress as expressed in the INA, i.e. DHS "shall remove" aliens found to be unlawfully present, Supreme Court failed to rule on a 4-4 split so the injunction is unlikely to be lifted.;
- DED - Deferred Enforced Departure. You should be removed from the US but the US Govt. has decided you fall into a class of people who shouldn't be removed for whatever reason. Currently only applies to Liberians;
- E-1 - treaty trader, allows entry for a person (and their dependents) who are engaged in "substantial trade" with the US. You have to be from a country that has a trade treaty with the US but virtually all developed countries do. This is a very complex category to apply for, requires a business plan, proof of on-going trade;
- E-2 - treaty investor, allows entry to engage in a specific business after making a "significant investment" and it cannot be a subsistence business. The most complicated non-immigrant category, requires a business plan and proof of funds. Due to a quirk in the Treaty of Ghent, British people resident in Canada cannot apply in Canada but must use the embassy in London. Note that E-1 and E-2 have a very limited form of "dual-intent", you can for example adjust status to being an LPR if you are sponsored for family reunification, but the only somewhat similar immigrant category is EB-5. Otherwise, you have to stay as E-1 or E-2 indefinitely and renew your status in two-year increments (this can be a problem when your kids hit 21 at they then have no status);
- E-2 CNMI - Scrapped in 2013. Similar to E-2 but for residency in the CNMI only, the criteria for this one is fixed though (e.g. investment amount) and there doesn't need to be a trade treaty to get it. There is also a "retiree" version of this category, so the investment can simply go into real estate;
- E-1/E-2 employee - an employee of a business approved as E-1 or E-2. Must be of the same nationality as the primary E-1 or E-2 holder and have specialized knowledge relating to the business. Note that spouses of E-1 or E-2 holders automatically qualify for open work authorization but children do not;
- E-3 - Australians working in a speciality occupation. Subject to a quota of 10,500 per year. Requires sponsorship by an employer on I-129 and an LCA. Similar to H-1B, but the spouse can be authorized to work immediately;
- EWI - Entered Without Inspection. Administratively assigned to people by the Border Patrol or an immigration court.
- F-1 - Academic student, requires the college to be registered with SEVIS, requires the student to have proof of funds, the course of study must be full-time. The college issues an I-20 which is used to support the visa application (Canadians are exempt from the visa requirement). Students can be authorized to work in various situations, such as "optional practical training" for a year after graduation (an additional 24 months for STEM students). Can also work for 20 hours a week on campus during the course of study. Also a rarely used option for students "suffering extreme economic hardship";
- F-2 - dependent of F-1, cannot be authorized to work;
- F-3 - cross-border student. Same as F-1 but the holder resides in Canada or Mexico;
- G-1, G-2, G-3, G-4 and G-5 - official govt. representatives to, and officers of international organizations and their dependents and servants - typically used by people who work at the UN, IMF, World Bank, etc.
- H-1A - since scrapped, used to be for nurses;
- H-1B - person in speciality occupation. This is the one everyone thinks they qualify for (assuming they have a good enough degree), but in reality the quota of 65,000 per year is largely used up by IT contractors. There are another 20,000 for people with master's degrees. Requires the employer to submit a "labor condition application" with the employer saying that it won't adversely affect Americans employed in the same occupation locally, proof the wages and hours are fair etc. Frankly books have been written on the subject of H-1B because it is viewed by many as being the main form of work permit to work in the US - my advice is for H-1B to be your last option, not your first. However bear in mind there are "cap-exempt" H-1B employers, usually institutes of higher learning and some other esoteric exemptions. Valid for three years in the first instance but can be renewed for another three years assuming certain requirements are met. If the holder has an approved I-140 filed for them and is simply waiting on an EB visa number, it can be renewed indefinitely.;
- H-1B1 - basically allows people from Chile and Singapore first go at the H-1B quota, 1,400 for Chile and 5,400 for Singapore;
- H-1B2 - your employer is the DoD and you're doing R&D;
- H-1B3 - distinguished fashion model, employer must file an LCA for this one too;
- H-1C - the replacement for H-1A, has a separate ridiculously low quota of 500 distributed regionally. This one is for registered nurses only and requires an I-129 and LCA be filed (as of 2012, this category was sunset and no more visas will be issued).;
- H-2A - seasonal agricultural workers, requires the employer to file an LCA, valid for one year at a time, employer must show compliance with basic labour standards such as housing and access to healthcare for the workers. Not subject to a quota either.;
- H-2B - temporary non-agricultural workers, subject to a quota of 66,000 per year, unless you work in the processing of fish roe products, or work on the CNMI or Guam. Same sort of requirements as H-2A but the work can be almost anything, commonly used by hotels and other seasonal businesses, e.g. soccer coaches for summer school, ski instructors etc.;
- H-3 - trainee, typically one who is getting training they can't get in their home country, at a place of business. This one is typically used for advanced medical training by medical students but can be for other things, but you can't be paid much. There is a quota of 50 on people getting "special education exchange" training. Two years maximum admission except for the "special education" trainees who are subject to an 18-month limit;
- H-4 - dependent of any of the H categories above. Generally speaking cannot be authorized to work, with a very limited exception for spouses of people on H-1B, provided the employer has an approved I-140 immigration petition and is simply waiting for a visa number;
- I - member of professional media and their dependents, there must be a reciprocal agreement with the other country. Typically you need your press credentials to get it;
- J-1 - Exchange visitor participating in an educational program approved by the State Dept. You need an approved DS-2019 from the college, school, whatever to get it. These programs are usually cultural in nature. Not just for students, commonly used by teachers as well. Typically valid for two years (which can cause problems with taxes as the exemption from residency only applies for those two years, so leave on time!) J-1 is subject to some complex rules, for example you can't reapply for say, H-1B until you've been out of the country for two years. Also there are rules designed to stop employers preying on foreign students;
- J-2 - Dependent of J-1. Can be authorized to work, unlike F-2;
- K-1 - Fiancées/Fiancés of US citizens. This is a transitional category, basically, you want to get married to a US citizen they sponsor you for K-1 on I-129F and within 90 days you have to get married, then you apply for adjustment of status (AOS);
- K-2 - Dependent child of K-1;
- K-3 - Spouses of US citizens. This is an effectively defunct category. It used to take a really long time for INS to process I-130s, so people would apply for K-3 because it was faster to get, then enter the US and apply for adjustment of status. AOS also took ages so the person could get an EAD and work while they were waiting. After the USA PATRIOT Act led to the creation of USCIS, things got much quicker and more efficient so this intermediate step is usually not of any benefit anymore;
- K-4 - Dependent child of K-3;
- L-1A - Intracompany transferee in a managerial or executive capacity. L-1 is one of the most complex non-immigrant categories because it is the most frequently used work authorized category. Basically you have to be employed by a company for a year abroad, then they can transfer you into the US, provided they meet all the requirements. "Managerial" for example doesn't mean a supervisor. L-1A is valid for three years and can be extended twice for a total of seven years. The employer has to file an I-129, or if the employer has a blanket petition in place, an I-129S. Canadians can apply at the POE. You can also enter to start a new office. If you happen to own the company (i.e. you basically self-sponsor yourself), you have to show some definite plan to leave, i.e. it's not dual-intent. Employer has to notify ICE if the person loses their job, etc.;
- L-1B - Intracompany transferee who possesses specialized knowledge or is a specialized knowledge professional. This is limited to five years maximum, then you must leave for at least a year. Note however that L-1A and L-1B can be "intermittent", i.e. you can extend indefinitely if you spend less than 183 days a year in the US. "Specialized knowledge" means your knowledge of company procedures and so on, but the "professional" means you have a professional designation, e.g. accountant or whatever.;
- L-2 - Dependent of L-1. Spouses can get work authorization by filing I-765;
- M-1 - Vocational student. Must attend an approved school, usually covers things like pilot training and other things that don't give you a degree at the end. M-1 students can get work authorization for practical training at the end of the course for six months maximum.;
- M-2 - Dependent of vocational student. Cannot be authorized to work;
- M-3 - Cross-border vocational student, i.e. you live in Canada or Mexico;
- NATO-1 through NATO-7 - Variety of classifications for people working for NATO. NATO-1 through 4 means officials and their staff in various capacities. NATO-5 are "experts" employed by NATO. NATO-6 are civilians employed by NATO. NATO-7 are servants and attendants of people in the other categories. Dependents are listed in the same relevant category. NATO-1 through 5 can enter the US without inspection. Dependents of NATO 1 through 6 can obtain work authorization. Note that NATO-6 holders and their dependents can obtain LPR status via EB-4.;
- N-8 - Parents of special immigrants, pretty rarely used, it means the child has got a way in via EB-4 (usually via NATO-6) and is classified as SK-3 or SN-3;
- N-9 - Children of special immigrants. Bit more common, as above but for the children (i.e. SK-1, SN-1, SK-2, SN-2, SK-4, SN-4) could also be a child of someone with N-8. Both N categories can be work authorized.;
- O-1A - People with an extraordinary ability in the sciences, education, business, or athletics. Employer files an I-129 with evidence of how fantastic you are, which is extensive. Valid for three years, can be extended for one year at a time after that;
- O-1B - People with an extraordinary ability in the arts or extraordinary achievement in motion picture or television industry. The agent typically files the I-129 so you can work for various different employers. Your ability to get this depends on how good of a bullshitter your agent is, you'd be surprised at some of the people who've gotten it. Officially you need various bits of evidence to show how extraordinary you are;
- O-2 - Support staff for O-1, must be "integral" to whatever the O-1 person is doing;
- O-3 - Dependent of O-1. Cannot be work authorized;
- P-1, P-2, P-3, P-4 - so-called "performance" category. P-1 is for professional athletes or teams, artists and entertainers, or "entertainment groups". P-2 is for artists and entertainers under cultural exchange programs. P-3 is for artists and entertainers whose performance is: "culturally unique". P-4 is for dependents. Maximum stay is typically one year, except for professional athletes who can stay for up to 5 years. Tricky to get P-1 as an entertainer as you have to get union approval;
- Paroled - this is an administratively assigned category and can be granted for various reasons. Say you no longer qualify for whatever category, you can be paroled in to collect your belongings. Say you've been put in removal proceedings, you can be paroled prior to your appearance in immigration court. There is for example a method of applying for parole for your relative if you are a Filipino WW2 veteran and your relative is waiting on an immigrant visa number;
- Q-1, Q-2, Q-3 - this is for "cultural exchange programs". Different from P-3 because there is no specific performance. For example a museum might have a Mongolian basket weaver visit for a few months to demonstrate the skill, as Q-1. Requires approval of the program by the Attorney General, so it's very unlikely anyone from the UK would qualify. Q-2 is for participants in the Irish Peace Process cultural exchange program and is defunct. Q-3 is for dependents. Can be approved for a maximum of 15 months;
- R-1, R-2 - Religious worker. Must be a non-profit religious organization. Valid for up to 5 years. There have been abuses of R-1 in the past so USCIS now checks very thoroughly to ensure you are actually a religious worker. Main users are Catholic ministers from El Salvador. R-2 is for dependents (which could be awkward for Catholic ministers), who cannot be authorized to work;
- S-5, S-6, S-7 - the so-called "snitch" categories. S-5 is for witnesses and informants relating to organized crime. S-6 is for witnesses and informants possessing information for terrorist-related investigations. S-7 is for dependents. S-5 requires certification from a federal or state law enforcement agency or the local US attorney, S-6 requires certification from a federal law enforcement agency or the local US attorney. Eligible for work authorization but cannot change status. Typically valid for three years but can be extended;
- Stay of removal - assigned by an immigration court. You were in removal hearings but a stay of removal was granted for whatever reason, e.g. you're a victim of crime and removing you would expose you to severe danger. You're Cuban and can't be removed, etc.
- T-1, T-2, T-3, T-4, T-5 - Victim of a severe form of human trafficking. Basically if you show up in a 55-foot container on a ship from India, etc. they aren't going to send you back, provided that you co-operate and returning you would expose you to the potential of: "severe harm". Certification by a law enforcement agency is required. T-2 through T-5 are for relatives of the T-1 holder who can be permitted to join the T-1 holder. Quota of 5,000 a year. Holders can eventually apply under EB-4 for LPR status;
- TN-1 - Trade NAFTA. You're Canadian and you're qualified in one of the occupations listed in 8 CFR 214.6 (which is a list of professional occupations). Can be applied for at the POE, requires a job offer letter explaining why they want you, why you're qualified and how long you'll be in the US (can't be more than three years). Can be reapplied for to extend the stay. Can also be applied for on I-129 by the employer. You can hold multiple TN-1s from multiple employers and the work can be part-time. Note TN status is not dual-intent and you must maintain non-immigrant intent. This is more of a problem with crossing the border than applying for AOS. You only show immigrant intent when you apply for AOS or an immigrant visa, not when the employer files the I-140;
- TN-2 - Same as above but you're Mexican. Mexicans however must apply for a visa from a consulate or embassy (unless they're already in the US) after the I-129 is approved;
- TD - Dependent of person holding TN status (doesn't have to be Canadian or Mexican). Cannot be authorized to work;
- TPS - Temporary Protected Status. Say you're in the US and you cannot return to your home country for whatever reason, usually a natural disaster. TPS for a class of people can be declared and you're allowed to stay temporarily and get work authorization;
- U-1, U-2, U-3, U-4 - Victim of crime. More general than S-5, so as a result the quota of 10,000 a year is used up. You have to help law enforcement as a victim to get it. The idea was that people unlawfully present were unwilling to come forward to report crimes, so this category encourages them to help. Certification required from the law enforcement agency. Can apply for LPR status after 3 years. U-2 through U-4 are derivative categories for relatives of the U-1 holder;
- V-1, V-2, V-3 - This category is defunct and was a way of bridging the gap for LPRs who filed for family reunification and had been waiting a really long time due to INS being fairly hopeless and the long wait time for second preference immigration visas. The I-130 had to be filed prior to 2000 so it's now long since defunct. However Congress has proposed a new version of the V visa which has yet to be enacted, but essentially it would be similar to the Canadian Super Visa. It would allow family members in preference categories who have a valid I-130 petition filed for them to visit for extended periods in the US, depending on the preference category. It would even allow adult children of US citizens and LPRs to get work authorization while waiting. Whether it will be enacted is an open question;
- VWB - Visa Waiver for Business, basically the same as B-1 but the visa is waived (if in fact you needed one), the maximum stay is limited to 90 days and you cannot change status, or adjust status unless in a category for which an immigrant visa is immediately available (which generally means parents and spouses of US citizens and a few other esoteric categories, such as former US citizens who are eligible to get their citizenship back).
- VWT - Visa Waiver for Tourist, basically the same as for B-2 but with the same limitations as for VWB. When you enter using the visa waiver program, the inspector at the POE will decide whether you're VWB or VWT;
- W - This is the proposed "guest worker" category which has come up in Congress a few times. Essentially it would permit the DOL to declare areas of the country to have a labour shortage and employers could then apply to bring people in temporarily. Similar to H-2B, but the quota would be dynamic and the LCA would be unnecessary because the DOL would have determined the labour shortage themselves, however the employer would still have to certify that the person would be paid an equivalent wage. IT workers would be specifically excluded. Some form of this might be enacted eventually but don't hold your breath;
- X - The proposed "entrepreneur" category. Similar to E-2 but there would be no requirement for a trade treaty and there would be a direct path to LPR status. Promoted by Bill Gates so likely to be enacted at some point. Renewable in 3-year increments, requires an investment of at least $100,000 and the hiring of at least three US person employees;
- Y - The proposed "retiree" category. You'd have to be 55 or older, own at least $500,000 of real estate (and live in it for at least 180 days a year) and have a healthcare plan, then you could live in the US. Renewable in two-year increments. This one is the brainchild of Charles Schumer and was designed to help the construction industry. Unlikely to be enacted as currently written because it contains some weird provisions for Canadian visitors (which are supposed to make it easier for them to visit but actually make it harder). Also the recession is now over so no point to it really.
These are broken down into two (or three) main categories, employment-based and family-based. The third one is immigrant investor, although technically it also an employment-based category. For most employment-based categories, someone, usually an employer has to file an I-140 petition and obtain labor certification from the DOL (the most important bit of which is usually that there are no Americans available who can do that job and the position is permanent). For family-based, the petitioner is the relevant family member and they file an I-130. For immigrant investors, the petition to file is an I-526.
Note there is an overall quota of 140,000 for EB-1 through EB-3 which is subdivided between the categories. If the quota isn't used up for EB-1, it is then applied to EB-2 and so on. EB-4 categories have their own quotas.
- EB-1A - Person of: "extraordinary ability". This is a higher bar than for O-1. Either you've got to have won the Nobel Prize or something similar or you've got to meet 3 out of 10 of the criteria on a list of things that show you are exceptional. This EB category is quite interesting because you can self-sponsor yourself for it;
- EB-1B - Outstanding professors and researchers. Once again, major prizes, or a pile of evidence.;
- EB-1C - Multinational manager or executive. Not quite so difficult to get and the most commonly used EB-1 category. The petitioning employer must be in the US unlike for L-1;
- EB-2 - Advanced degree or exceptional ability. You've got a master's or better (or a bachelor's and equivalent experience) and the job requires that level of skill or you've got three out of seven on the "exceptional ability" criteria list;
- EB-2 NIW - National Interest Waiver. Basically the same as above but you're arguing that you don't need a labor certification from the DOL because you would: "greatly benefit" the United States. Like EB-1A, you can self-sponsor for this one. Personally never heard of anyone managing to get this one, very high bar, easier to go with EB-1A as the criteria are less subjective;
- EB-3 Skilled workers/Professionals - This is the most basic EB category, you've got to have at least 2 years experience or a bachelor's degree and there can't be any Americans available that can do it. Although it's easier to apply for, you're much further down in the quota so don't be surprised if there's a wait for a visa number. At the time of writing the wait isn't too bad, only a few months. Unless you're subject to a per country limit (e.g. you're Indian). The trick to this one is to make sure you apply for it in good time if you're on H-1B or L-1;
- EB-3 Non-skilled worker - Technically the most basic EB category but in reality almost impossible to get because making out that there are no other unskilled workers available in the US to do your job is hard so the labor certification can't be completed;
- EB-4 Special immigrant (SK-1, SK-2, SK-3, SK-4) - You were in the US as G-4 and retired, you and your spouse can apply for AOS in these categories;
- EB-4 Special immigrant (SN-1, SN-2, SN-3, SN-4) - You were in the US as NATO-6 and retired, you and your spouse can apply for AOS in these categories;
- EB-4 Religious worker - More narrow than for R-1, you have to be a minister of religion and have to have been one for at least two years. Used to be broader but various abuses led to Congress narrowing the definition in 2012;
- EB-4 Special Juvenile Immigrant - a juvenile who has been declared dependent on a court somewhere in the US and who cannot be returned to their country of origin for reasons determined by an immigration court. This one is heavily used at the moment because of the number of unaccompanied minors who came up from central America, so there is now a wait for a visa;
- EB-4 Other special immigrants - There are a number of other obscure categories, some of which are defunct. E.g. long-term employee of a US mission abroad, broadcaster working for the BBG (aka Voice of America), etc.
- EB-5 - Immigrant investor. You have to invest at least $1 million in a business and hire directly or indirectly ten US citizens and/or LPRs over two years (or preserve ten jobs in a "troubled business"). If the investment is in a: "targeted employment area" then the investment only has to be $500,000;
- EB-5 Regional investor center participant - Essentially the same as above but someone sets up a regional center and you invest the money in that center and it creates the jobs and you get LPR status that way. This one is really controversial because there have been some huge scandals associated with it. So there is a proposal to up the investment amount to $1.2 million (or $800,000 in a TEA), limit the places that qualify to be a TEA (basically rural areas and some very high unemployment urban areas like Baltimore and Brooklyn) and the jobs created would have to be direct jobs, i.e. you would need their W-2s but it's not in place yet. There is a quota of 10,000 for EB-5. More than 80% of people who use it are Chinese, so much so that the per-country limit has kicked in. If you're not Chinese there are visas immediately available but it's not clear if Congress will amend or kill this program;
- EB-6 - This is a proposed category which is similar to X mentioned above, championed by Bill Gates etc. but it is so similar to EB-5 that it's not clear it will happen, or possibly EB-5 will be amended in some way;
- Visa immediately available - Spouses and parents of US citizens. By far the #1 way in which people gain LPR status in the US. More than a third of people who get LPR status do it this way.
If you fall into one of these you should check the State Dept. Visa Bulletin. Do not make the common mistake of taking today's date then deducting the date in the bulletin and figuring that's how long the wait is - the wait is based on the quota, it does not move forward day-by-day with the date. You can get a very vague idea by checking several months worth of bulletins and establishing a trend line - but even that is not terribly helpful because since the forms were put on the internet back in 1998, the demand has grown exponentially.
- F1 - Unmarried adult sons and daughters of US citizens, quota of 23,400 a year;
- F2A - Spouses and minor children of LPRs. The only one of these categories where you might get it in less than a couple of years;
- F2B - Unmarried adult sons and daughters of LPRs;
- F3 - Married sons and daughters of US citizens (note no equivalent category for LPRs), another quota of 23,400 a year. You'll be waiting a really long time for this one. The reason for the legislative difference based on marriage appears to be because F3 immigrants are more likely to have dependents;
- F4 - Siblings of US citizens. Quota of 65,000 a year. More I-130s are filed for this preference category than any other and the wait time for a visa is epic. Looking at current State Dept. statistics, if you filed an I-130 in June 2011 (which is where USCIS are at the time of writing), you'd expect to get a visa around November 2041, assuming you are from a country without a per-country limit (e.g. Mexico) and everyone who applied actually bothers to apply for a visa. Plus USCIS has nearly a million outstanding petitions it hasn't processed yet! The only reason to file a petition for F3 or F4 at this point is because Congress might change the law in some way that shortens the wait;
Note that Congress is thinking of changing this system because it is obviously bonkers. The main proposal is that F1, F2B and F3 would be combined into a single preference category, F2A would be scrapped and spouses and children of LPRs could get visas immediately, and F4 would simply be abolished.
- Asylees - Same as a refugee, except this is a person already in the US (for less than a year) or someone who physically shows up at a POE;
- Cubans - Can apply for AOS after having been in the US for at least one year (typically as B-2). There is also a Cuban "lottery" but it is effectively defunct;
- Diversity Immigrant Visa Program - the so-called: "green card lottery". Very rarely available in English-speaking countries with lots of white people because obviously the US already has a lot of white English-speaking people in it, although there are usually a few available for Northern Ireland. 50,000 visas available per year. Congress is talking about scrapping it, although it will probably just be scaled back as the Congressional Black Caucus want to keep it going for a few African countries;
- Refugees - a person who has a well-founded fear of persecution on account of race, religion, nationality, membership in a particular social group, or political opinion. Usually this is determined by the UNHCR and the State Dept. then agrees with the UNHCR on the number they will accept. However the President also has the power to define what a "refugee" is by executive order;
- Jay Treaty - Canadian First Nations who qualify under the Jay Treaty. Technically not immigrants, they have a right to LPR status at birth and simply have to apply for registration with the US Embassy in Ottawa. Also, this LPR status is permanent and cannot be removed by an immigration court because of criminal activity for example;
- Alien who renounced US citizenship - basically, you were born in the US (or have some other direct claim, e.g. through your parents), renounced US citizenship and now want to return;
- SB-1 - a person who lived in the US as an LPR and then went abroad for more than a year and didn't get advance parole first. You must show that the circumstances of your extended stay abroad were beyond your control. Technically an immigrant visa.