An addendum, I am not even trying to dictate how the file I submitted be used. I tried to indicate that in the file. One could even use the normal zic output or create one binary file named "Abbr" or "foobar", do a binary search for which file to open from the normal file output of zic. This amounts to two files being read. Again, not trying to limit any possibilities nor suggestions for its use or non-use. This was in response to "required by employer", and I will "force you to do it my way". You may also decide to build structures for more exact ID of a zone origination. This was clearly beyond what was my intent, but super glad it got the thought process going. Steve