The most common and most likely answer to this crossword clue is the 11 letter word TALLAHASSEE
I've seen this crossword clue in The Times
T
A
L
L
A
H
A
S
S
E
E
More clues leading to the result TALLAHASSEE
- Feel atlas has gone wrong, missing out fine US city
- Treat all these as a capital
- Hard to believe that’s it — look round South American city
- Unlikely American has regularly visited scene in capital
- A diocese that has parts south of big Florida city
- God and fool welcomed by supporter in US city
- Unlikely admirer initially has date in US city
- Unlikely — a diocese that has parts in Florida city
- City thanks all residents — has church following
- Unlikely start to August: gets to visit American capital
Buddy explains!

The straight part
We know that "US city" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case us city = tallahassee.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.