If you're coming to the United States as an immigrant or with a nonimmigrant visa (or from one of the countries that doesn't require you to have a visa), the first person you meet on arrival—whether you come by air, land, or sea—will be an officer of U.S. Customs and Border Protection, or CBP.
The CBP officer will inspect your passport, looking for verification that you've been given permission to be in the U.S., and ask you questions designed to elicit any information that might prohibit you from entering. If arriving on an immigrant visa (the entry document for new lawful permanent residents), you might also need to hand over a sealed, unopened envelope containing your immigration file. (If you received one. In some cases, this information is transmitted electronically; a notation in your visa saying "IV Docs in CCD" would be your clue that this is the case.)
Have all your paperwork ready. CBP officers are trained to be skeptical, and security is their first concern.
You might encounter long lines of people waiting to be screened at "primary" inspection. All passengers are screened at primary inspection and the officer will take your fingerprints digitally (unless you are exempt from this requirement due to age or your visa type).
The officer at primary inspection will verify your identity and check your name against various computer databases. The officers are on the lookout for people who might be a security or health risk or who are using a tourist, student (F-1 or M-1) or some other nonimmigrant visa to gain entry to the United States for illegal purposes or a permanent stay.
Even if your visa and intentions are valid, if the CBP officer finds a problem that can't be resolved quickly or believes you're being dishonest or are a security risk, you will be sent to a secondary inspection area for a longer interview.
If an officer in secondary inspection determines that you are not eligible to enter the U.S., you can be refused entry at the border, returned to your home country, and even prohibited from returning for five years or from using the Visa Waiver Program or "VWP" (if you are from a country that does not require a visa.)
All immigrants entering the U.S. for the first time with a green card will be sent to secondary inspection, so that an officer can review your file. Do not be alarmed when you are directed to secondary inspection; it's the normal process.
One way to ensure a smoother, shorter entry to the U.S. is to apply to a U.S. government Trusted Traveler program, available only to people from countries considered low-risk. Approval will mean that, instead of standing in the long passport-control and inspection lines, you will be able to enter using a kiosk (located at designated U.S. airports).
The exception is if you are bringing in certain goods or large amounts of currency, in which case you must go through the main inspection line even if you've been approved as a trusted traveler.
Here are the most likely questions you'll have to answer. However, the officer is free to ask you just about any question. Try to remain polite and calm and don't take it personally if the officer seems abrupt; CBP officers are trying to screen a lot of people as quickly as possible.
Why are you visiting the United States? Your answer must match your visa (or the legal requirements for admitting you without a visa). If, for example, you have a B-2 visitor visa but say that you're coming to find a job, you'll be put on the next flight or bus home. Or if you're entering with a marriage-based green card, you obviously don't want to say, "to get a divorce." Your answer must also show that you don't plan to violate any U.S. laws.
Where will you be staying? Particularly if you're coming to the United States for a temporary stay, the officer wants to know that you have clear plans for what you will be doing there. If you have no previously arranged places to stay, the CBP officer might question whether you should be allowed in.
Who will you be visiting? Again, this is a question directed mostly at tourist visitors. The officer is looking to see that you have clear—and legal—plans.
How long will you be staying in the U.S.? If you're coming in with an immigrant visa (have been approved for U.S. permanent residence), you won't likely be asked this. For short-term visitors, however, the officer wants to know that you don't plan to stay longer than you should. Even if your visa says "multiple entry" and is valid for ten years, you will usually not be allowed to remain for more than six months on a B-2 tourist visa—the I-94 arrival/departure record that's created for you (with some exceptions for entry by land, such as Canadian tourists or Mexicans with Border Crossing Cards) will tell you the date by which you must leave. The I-94 is available only online if you arrive by air or sea. Other entrants might receive a little white card stapled into their passport. If you are entering the U.S. on a work visa or student visa, you will be admitted for the amount of time that corresponds with your job or program (called "duration of status," with the symbol "D/S"). Be sure to access your online I-94 soon after arrival (if you didn't receive a physical one), to make sure it has the correct immigration status and expiration date. You're expected to carry the printed copy around with you, as proof of having been lawfully admitted to the United States.
How much money do you have available for this trip? Who is paying for your trip? These are questions for temporary visitors; the officer wants to know that you will be able to cover your expenses while in the United States, for the amount of time you plan to stay.
Have you visited the United States before, and if so, how long did you stay? If you previously stayed in the U.S. longer than you originally planned or were permitted to, the officer will want an explanation and might ask for evidence to corroborate your answer. For example, if on your last visit you told the officer you were visiting Disneyland for one week, but ended up staying two months because you were very ill, the officer might ask you for medical documentation and proof that you paid your hospital bill. Even if you did not "overstay" the amount of time you were permitted to stay, a previous long stay will likely require explanation.
If you have previously stayed in the United States for six months longer than allowed, you might not be eligible to come to the United States again without special permission called a waiver (unless you've already waited outside the United States for at least three years). If your overstay lasted a full year, you might be punished by having to remain outside the U.S. for ten years before trying to return. If you are from a country that does not require a visa and you stayed longer permitted on a previous visit, you might be required to return to your home country and obtain an actual visa.
How often do you come to the United States? The CBP officer is looking for people using a tourist visa (or the right to enter without a visa) as a way of living permanently or working in the United States. If the officer determines you are misusing the visa, you will be denied entry.
Have you been vaccinated against COVID-19 and can you prove it? This question is no longer asked of most international travelers, with the exception of those entering by a land border. See the DHS's Fact Sheet: Guidance for Travelers to Enter the U.S. at Land Ports of Entry and Ferry Terminals.
Foreign nationals attempting to come to the United States, either temporarily or permanently, have few rights during the application and screening process. You do not have the right to an attorney in primary or secondary inspection, but might be permitted to do so, depending on the situation. Your bags and electronics can be searched without your permission, for any reason, and CBP officials can ask you almost any question.
Also see Can U.S. Border Officials Legally Search a U.S. Citizen's Electronic Devices?, the analysis for which also applies to U.S. permanent residents.
Only in rare cases, such as if you fear persecution in your home country and are seeking protection (asylum), and the CBP officer believes that your fear is credible (believable), will you be allowed to appear before an immigration judge to prove that you should be allowed into the United States.
The border official can also check your suitcases and personal possessions, so:
Make sure nothing that you bring appears to contradict your visa status. If you are coming as a tourist, don't bring along a book on how to immigrate to the United States or a stack of résumés. You might have these things simply because you have future plans to apply for immigration, but the CBP won't likely see it that way.
Do not bring illegal or questionable items. It might be legal in your country to carry a firearm (a gun) or marijuana, but it is not legal to bring it into the United States. If you have contraband in your luggage, it could lead to your immediate removal. Make sure you are not carrying other illegal or questionable items, such as illegal drugs, pornography, or plants, fruits, and animals of types or species that are not allowed into the United States.
If you are arriving from a designated country with high rates of a communicable disease of current concern, you will be asked to complete a health form. Then, after you pass the customs and immigration checks, you will undergo additional screening. This might involve taking your temperature or other medical screening.
With regard to COVID-19 these procedures can change on short notice, so check the Centers for Disease Control's page on International Travel for the latest.
For more information on when you can be legally excluded from the United States, see Inadmissibility: When the U.S. Can Keep You Out. And for details on getting a visa, understanding the privileges and responsibilities it comes with, and successfully entering the United States, see U.S. Immigration Made Easy, by Ilona Bray (Nolo).