Since many are asking if they can get married on a tourist visa in US to their American sweetheart, it is best to discuss this issue now.
There is nothing in the US Immigration law that proscribes one from marrying on a tourist visa. As a general rule, a foreign national can get married while in the US on a tourist visa, but with certain conditions. The scenario is, you enter on a tourist visa, get married to a US citizen and come back to your country of origin before your tourist visa expires and once in your home country, apply for the applicable visa to get back to the US and stay with your spouse.
Although this process is perfectly legal, it is not easy to convince the Consular Officer and the Immigration Officer at the border that you have no preconceived intention of getting married with a US citizen. There must be a very convincing evidence that your trip to US is totally for recreation purposes and that you will be back to where you came from after the allowed period of visit.
There are those who successfully entered the US soil on a tourist visa, got married and immediately apply for Adjustment of Status. It could also be possible but under an extraordinary case. Example, a foreign national traveled to US to visit a family member and while on visit, happened to fell in love with a US citizen and both agreed to marry each other. If this is the case, the foreign national need not return to his or her foreign country and will just have to apply for Adjustment of Status at the US Immigration Office to be allowed further stay in the US. Many are aware of this course and many are up to this process, but what they are not apprised of is the condition attached to the AOS application and how the Immigration Officer would act on the application.
To the mind of the Immigration Officer, situations like the one cited above is a complete circumvention of the immigration laws on fiancé or spouse visa. Why? While a fiancé or spouse visa is an entry visa for a more or less permanent stay in US, tourist visa is for a temporary stay visa. Each visa has its own standard rules and procedures to follow. Hence, if one wants to get hold of a visa the odd way, doubts arise as to the true intent of the applicant. Thus, stricter scrutiny is employed to overcome the doubts. Efforts must be taken by the foreign national applicant that indeed, there was really no premeditated intention to marry at the time of entry to US on tourist visa. You must be very lucky if you have been issued a change of status not through the normal method. Otherwise, you may be charged of visa fraud, get deported and can be banned to enter the US soil forever.
Also, the foreign national applicant for Adjustment of Status is not allowed to leave US until the adjustment is approved or an advance parole is issued. Are you ready to leave behind what you have been in your home country all your life?
Consult before you plan. For sure, you will have a good living for a lifetime.