You can enter the US through over 300 PortsofEntry (POE). A POE is any station: land, air or water, through which a person can enter the US. Immigration officials inspect all persons entering the US at a portofentry.
At the port of entry, an official must authorize the visitor's admission to the U.S. At that time Form I94, Record of ArrivalDeparture, which notes the length of stay permitted, is stamped. Those visitors who wish to stay beyond the time indicated on Form I94 must contact the USCIS to request Form I539, Application to Extend Status. The decision to grant or deny a request for extension of stay is made solely by the USCIS.
