The most common and most likely answer to this crossword clue is the 5 plus 6 letter word SANTA MONICA
I've seen this crossword clue in The Times
S
A
N
T
A
M
O
N
I
C
A
Buddy explains!
The straight part
We know that "US resort" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case us resort = santa monica.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.