B-2 visa holders are generally given six months when they enter the U.S., with the possibility to extend their stay for another six months, given valid reasons. You can apply for an extension of your B-2 tourist visa while in the United States by filing a Form I-539 with the U.S. Citizenship and Immigration Services. The USCIS states that the normal processing time is 60 days, but that you may apply up to six months before your I-94 expires.
You must hold a passport that is valid for the entirety of your requested amount of time in the United States, submit form I-539 with personal information and an explanation of how you are financing your stay, have not violated the terms of your visa, pay a $300 fee and be prepared to justify your request for an extension. The USCIS cautions, however, that meeting all of these requirements does not guarantee you an extension; officers may approve or deny your application at their discretion.
Send the form and the $300 filing fee to either the California service office (USCIS California Service Center, P.O. Box 10539, Laguna Niguel, CA 92607-1053) or the Vermont service office (USCIS Vermont Service Center, ATTN: I-539, 75 Lower Welden St., St. Albans, VT 05479). After the application is received, the USCIS will send you a receipt with an estimated processing time and a tracking number that you can check the status of your application with through its website.
