600 Subfield $z - Geographic subdivision:

Subfield $z contains a geographic subject subdivision. Subfield $z is appropriate only when a geographic subject subdivision is added to a name or name/title.

Examples:

600 00$aFrederick$bII,$cHoly Roman Emperor,$d1194-1250$xHomes and haunts$zItaly.

600 10$aFord, Gerald R.,$d1913- $xMuseums, relics, etc.$zMichigan.