US Port of Entry Applicants should be aware that a visa does not guarantee admission to the United States.  The U.S. Customs and Border Protection of the Department of Homeland Security (“USCBP”) has authority to deny admission.  Also, the authorized period of stay in the U.S. is determined by USCBP, not the consular officer.  Upon admission to the U.S., a USCBP official validates USCBP Form I-94, Record of Arrival/Departure, which notes the length of stay permitted.  Therefore, a nonimmigrant’s stay is governed by the expiration date on his or her USCBP Form I-94, not the expiration date of the visa.  Those temporary workers who wish to stay beyond the time indicated on their USCBP Form I-94 must file to extend their stay prior to the date their authorized stay expires.  The decision to grant or deny a request for extension of stay is made solely by the U.S. Citizenship and Immigration Services.