Medium-sized cities and/or large counties by population in the US to be possible targets.

There's a few medium-sized cities in Florida

Tallahassee, Gainesville, Port St Lucie....

Port St Lucie is of a healthy mid-size of about 220,000, if not 260,000.

It is in St Lucie County, which is a large population center of over 300,000.

A lot of counties in South Florida can easily approach 200,000+ even if there's small-mid-sized cities.

I realized that if the goal is to inflict maximum casualties, St. Lucie County would likely be a secondary target.

Big cities aren't the only civilian targets. Mid-sized cities like Port St Lucie or large counties are unfortunately on a list of possible targets in a nuclear war.

There are not a lot of places to go to in Florida it's too narrow, even if you lived in the countryside. There's probably a mid-sized city not more than 2 hours out from you. (Edit: Anywhere that has satisfactory jobs)

California & Texas are probably the only other states I can think of that have mid-sized cities pretty close by.