Hundreds of thousands of people receive what's commonly called a tourist visa each year. (The visa is more technically known as a visitor for pleasure visa, in category B-2.) Yet many also apply and get denied. The U.S. visitor visa allows visits to the U.S. for pleasure purposes, or for medical treatment, for a maximum period of up to six months.
Though the United States certainly wants visitors, even if just for economic reasons, it also has reasons to be careful and deny some visas, for legal reasons discussed here. The fundamental principle behind this is that the U.S. can find visa applicants "inadmissible" for any of various reasons.
The U.S. government is serious about making sure that people use their visas only for the purposes for which they were intended, and do not stay beyond the expiration date of their permitted stay (usually shown on Form I-94), which for tourists is usually no more than six months.
The actual length of your U.S. stay will be determined when you reach a legal port of U.S. entry. Once in the U.S., if you need to stay longer, you can apply for an extension of up to six additional months, but if your stay extends beyond this overall period (one year total), you will begin officially overstaying your tourist visa, thus potentially subjecting yourself to serious immigration consequences.
But these consequences aren't enough to stop many people from overstaying, and the U.S. government doesn't want to have to constantly track down and arrest people who overstay. That's part of why U.S. immigration authorities are charged with a security role, making sure that people who present any sort of risk to the U.S. are not allowed entry in the first place, regardless of the type of visa they apply for.
Although the application process for a B-2 tourist visa is fairly straightforward, the last thing the U.S. government wants is for this to become an easy means of entry for people who actually want to work in the U.S. (which is prohibited for B-2 visa holders) or stay and live there long term.
For that reason, every applicant must show "nonimmigrant intent," or prove that they really plan to act like a tourist and leave on time. In order to prove this, the State Department demands evidence that:
You will be expected to provide documents proving all these things. For example, you should bring to your consular interview copies of your travel itinerary (including hotel reservations in the U.S.), plane tickets (including a return ticket out of the U.S.), home and apartment leases, bank statements, and so on. Failure to provide convincing proof will result in your B-2 tourist visa request being denied.
Your answers to questions at the visa interview will also be important. For example, if you say that you plan to "Visit Disneyland, and maybe pick up some part-time work there," or that you're "in a hurry to enter the U.S. to marry your girlfriend there," you will be told that you are applying for the wrong visa, and denied.
Looking at the list of items you have to provide for a U.S. tourist visa, some applicants are tempted to simply lie, or cover up certain facts. For example, they might deny a past criminal conviction, or that they have U.S. citizen family members in the United States. This is, however, visa fraud, and once discovered, will lead to a denial.
Fraud could also come up as an issue in the future if your file shows past lies regarding U.S. visas you have applied for or obtained. Learn more about the effect of submitting false information on immigration applications.
If you have a criminal record, or history of espionage or any links with terrorist groups, there is a strong chance your request for a U.S. visa (of any sort) will be denied. (See What Crimes Make Immigrants Inadmissible to the U.S.?)
Not every crime is grounds for a denial, but many are, and the list can be difficult to interpret. You'll want to consult an experienced immigration attorney.
If you have overstayed your permitted time on a past U.S. visa, or spent periods of time in the U.S. without authorization, you might have difficulty persuading the consular officer reviewing your visa application that you won't violate this visa, as well.
In fact, if your unlawful presence in the U.S. added up to 180 days or more, you face an automatic bar to entry of three years. That number goes up to ten years if your period of unauthorized stay was one year or more. For details on that, see Three-Year and Ten-Year Time Bars for Unlawful U.S. Presence.
As mentioned, U.S. immigration laws contain a long list of reasons that people may be found "inadmissible" or ineligible for a visa or green card. For example, if you have an illness of public health significance (most likely tuberculosis), or have been removed (deported) from the U.S. in the past, or are a drug abuser or addict, you can expect to be denied a visa. See Who Can't Get Into The United States? for more information.