[['county', 'tunnel', 'type', 'length (imperial)', 'date of opening'], ['londonderry', 'castlerock', 'rail', '668 yd', '1845 - 1853'], ['londonderry', 'downhill', 'rail', '307 yd', '1845 - 1846'], ['armagh', 'lissummon', 'rail', '1759 yd', 'early 1860s'], ['down', 'binnian tunnel', 'aqueduct', '2.5 miles', '1948 - 1952'], ['antrim', 'whitehead', 'rail', '145 yd', '1862 - 1994'], ['tyrone', 'dungannon', 'rail', '800 yd', '1862']]
In The List Of Tunnel in northern ireland , United Kingdom , the Castlerock and Downhill Tunnel are based in County Londonderry
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