The place of first publication of a work is the place where that work is first published. if a work is published commercially, that place is generally the location of the publisher. For copyright purposes, only the country matters, the exact location within the country is not important.
(A later edition may or may not be a separate (derivative) work, with its own copyright term.)
Also, the statement that "if a work has entered the public domain in its place of first publication, it is in the public domain everywhere." is simply incorrect. There are, for example, cases where a work is under copyright in the US, even though it fell into the public domain in the country where it was first published. If a work first published outside the before 1964 US entered the public domain in the US because the US copyright was not properly renewed, but the copyright was restored under the Uruguay Round Agreements Act, the restored US copyright has the full length of the US copyright term (95 years from first publication for works published prior to 1978), even if the 'home' country grants a shorter term of protection. In general, the US does not follow the "rule of the shorter term" and US copyright terms depend on US law, no matter if the home country grants copyright for a shorter period.