To explicitly mark placenames, both in the original text and in translations or commentary, we use <placeName>:

<placeName>Rochester, NY</placeName>

<placeName>
	<settlement type="city">Rochester</settlement>,
	<region type="state">New York</region>
</placeName>

It is not necessary to be too much detailed in this cases, the <placeName> is open.

See more options and classifications in: TEI-C Place Names.