There are conventions that are wrong. My opinion is correct and preempts incorrect conventions. It is standard to omit place-level labels such as "State of" but especially in the United States of America, the word "County" is critical, especially since so many counties have the same name as a town within, or without the county. Double commas look ugly. In the United Kingdom, using the suffix "-shire" makes the word "County" unnecessary.
I wrote to the Family History Library to protest how my ancestral town, Castelcivita, works, as
Castelcivita, Salerno, Campania, Italy
but it did not accept the previous name, in use until 25 January 1864, of Castelluccia. Neither did it accept the name of the country, Kingdom of the Two Sicilies. Well, it looks like they follow a good policy of omitting "Kingdom of" and now they allow me to use
Castelluccia, Principato Citeriore, Two Sicilies
Which is just as well, since people would be forever researching what day the Town of Boston became the City of Boston, and when Kingdom of Italy became Italian Republic.
Place names need to be readable by computer programs, to help match events on one database with events on another database, and to match people on one database with people on another. Because of this, and because of so many places that straddle political boundaries, software needs to allow multiple place names for the same event:
2 PLAC Saint Mary's Cemetery, Salem, Essex County, Massachusetts, United States of America
2 PLAC Saint Mary's Cemetery, Peabody, Essex County, Massachusetts, United States of America
This allows a program to match a person to either place name in another database.