King visiting apparently empty county? (7)

I believe the answer is:

norfolk

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'county?' is the definition.
(I've seen this before)

I don't understand how the rest of the clue works.

(Other definitions for norfolk that I've seen before include "Eastern county" , "Part of East Anglia" , "Broad area" , "Part of country" , "County of Norwich and Sandringham" .)

I've seen this clue in The Independent.

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