Historical county of Northern Ireland in which the Giant's Causeway is situated (6)

I believe the answer is:

antrim

(Other definitions for antrim that I've seen before include "NI town" , "town in Ireland" , "Part of Ireland" , "Irish county of musically green glens" , "County in Ireland's north-east" .)

I've seen this clue in The Independent.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.