A state name paired with a city name “is in effect a parenthetical element,” states Words Into Type. It makes the “preceding reference more specific.” The state name needs to be set off with commas. The Chicago Manual of Style gives similar instruction.
Yet a lot of writers and even some editors set off the state name with only one comma. This can lead to confusion, making the meaning of a sentence hard to comprehend.
This sentence looks like a strange series: “Only Lake City and Tallahassee, Florida and Biloxi, Mississippi have bus stations located downtown.”* It looks like three elements: (1) Lake City and Tallahassee, (2) Florida and Biloxi, and (3) Mississippi. that’s how the commas separate the names. Adding commas after Florida and Mississippi would help: “Only Lake City and Tallahassee, Florida, and Biloxi, Mississippi, have bus stations located downtown.” (By the way, “only” referred to stops between New Orleans and Jacksonville formerly served by Amtrak and currently served by intercity buses.) We could insert those commas and consider the sentence adequately edited; the context indicates which items have stations (the cities, not the states).
However, I still wouldn’t be completely happy with it. The context doesn’t come until the end of the sentence. Reordering the sentence would be one solution: “The only downtown bus stations are in Lake City and Tallahassee, Florida, and Biloxi, Mississippi.” We could also follow the rule that when a series comprises items that themselves contain commas, the items should be set off with semicolons: “The only downtown bus stations are in Lake City and Tallahassee, Florida; and Biloxi, Mississippi.” To me, that semicolon in the middle of the sentence looks funny. William Safire, longtime writer of the New York Times Magazine “On Language” column, advised getting rid of anything that looks funny.
We could put the abbreviated state names after each city and set them off with semicolons: “Only Lake City, Fla.; Tallahassee, Fla.; and Biloxi, Miss.; have bus stations located downtown.” I’d consider that satisfactory if kind of heavily puncuated.
For this sentence, parentheses might work well for setting off the state names: “Only Lake City and Tallahassee (Florida) and Biloxi (Mississippi) have bus stations located downtown.” Still, the proximity of (Florida) to Tallahassee might not clearly communicate that Lake City is also in Florida.
My final choice would be to use parentheses and add a few words: “Only Lake City and Tallahassee (both in Florida) and Biloxi (in Mississippi) have bus stations located downtown.” I think that’s clear and reads smoothly.
Can you offer a better solution? If so, please post a comment.
* David Peter Alan, “Is Amtrak Coming Back to the Gulf Coast? Bus Service in the Gulf Coast Region Is Weak,” National Corridors Initiative Destination Freedom, April 18, 2016.