State abbreviations:

1. can be found in the AP Stylebook.

2. are not the postal abbreviations (e.g., California is Calif., not CA; New York is N.Y., not NY).

3. are not needed if the city is a dateline city (see AP).

4. are nonessential clauses, and, as such, are set off by commas on both sides!
E.g., The Lions will travel to Hanover, N.H., on Saturday.
West Palm Beach, Fla., is full of old people.

-Amy