A lot of sloppy ways have been devised to write place names in genealogy documents. Sometimes, the result is simply unattractive copy. In other cases, the result is ambiguity or utter loss of intelligibility.
Why the word county is so important.
Many counties have the same name as a locality in the same State. To distinguish Merrimack County, New Hampshire from the Town of Merrimack, (which is in Hillsborough County, New Hampshire) it is common to prefix a comma, as follows:
One problem with that is, it is ugly. Further, it doesn't really establish that the writer meant Merrimack County. The reader of a genealogy document has no guarantee that the writer follows the convention of omitting the word county. Consider:
Which is the City of Concord, in Merrimack County, and
Which is part of the Town of Merrimack, New Hampshire.
For localities in Great Britain, on the other hand, the word county is not often used with the county; and to distinguish a county from a locality, the suffix -shire will usually do.
Why the county is so important.
Since the county is often omitted from an address, one might well wonder why it is even necessary to include it in a genealogy document. Consider UNION, OHIO. Brookes Universal Gazetteer (1832/1850) gives dozens of different localities named Union in Ohio. The use of the county name helps the reader to know which Union the writer means, and the county helps a researcher to locate records.
Why the country is so important.
Genealogy documents find their way through the internet to readers all over the world. Did you mean Georgia, U.S.A. or the Republic of Georgia? While you may know what you mean, a reader not fluent in your language, in another part of the world, might not.
Why not to abbreviate.
Abbreviations come and go. They can also mislead. Lincoln, NB can mean Nebraska or New Brunswick, as they both have places named Lincoln. At first, Nebraskas official postal code was NB. There was a time when MS meant Massachusetts.
Only in the cases of U.S.A. and U.S.S.R. is it even necessary to abbreviate. In all other cases, write it all out.
You may be tempted to use Co. for County but it also means Company, and why not just write it out?