LATA is an acronym for Local Access Transport Area. This is a geographic region which has boundaries which usually defines how and by whom your long distance phone calls are billed. A long distance call made to someone within your LATA is said to be IntraLATA and is often also referred to as a local toll call. Calls that cross LATA boundaries are said to be, of course, InterLATA and are by default handled by ATT, MCI, Sprint, etc. Those are long distance calls.