In a state, cats set off with Shamus (13)

I believe the answer is:

massachusetts

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'in a state' is the definition.
I can't judge whether this defines the answer.

'cats set off with shamus' is the wordplay.
'off with' indicates anagramming the letters.
'cats'+'set'='catsset'
'catsset' with its letters mixed up with 'shamus' can make 'MASSACHUSETTS'.

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(Other definitions for massachusetts that I've seen before include "A NE US state" , "US state, capital Boston" , "New England state" , "One of the original 13 US states" , "Bay State" .)

I've seen this clue in The Telegraph.

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