David Speers of Causeway Books recognised the place-name as Lagadrade and Pat McKay of the Northern Ireland Place-Name Project at Queens University Belfast provided the following derivation:
It seems that Irish Log an Droichid 'hollow of the bridge/crossing place' is the most satisfactory interpretation as suggested by the local pronunciation and that 'Logenadoaid' is a corruption. Info on pronunciation of 'Cowenfishyn' as 'Carnfishin' is also interesting. I'm sure the first element is Irish 'carn' but the final element is obscure.
Carnfishin is in the townland of Ballyhemlin and Lagadrade might overlap the townlands of Magheraboy and Ballaghmore.