I decided to look for James O'Kane in the Irish Census Records. These are online for 1901 and 1911. The only James O'Kane who was 78 in 1911 (ie born 1832) lived in the townland of Tullykeeran. He also had a son Francis and this fits with the Frank O'Kane who communicated some of his father's songs to Sam Henry. I consulted the 1 inch Ordnance Survey map of the area (Third Series, revised 1958-9, amended 1967) and find Tullykeeran at 280404 (to the nearest kilometre). About 3 km away, to the south-east, towards Maghera, is Killelagh Lough. This must be the place given in the song as Killylough or Killyleagh. Of the other places mentioned in one or other version, Macknagh is a further 3 km west of Killelagh. Halfgain is not on the maps I've been looking at but is within about a km to the south-east of Maghera.

The two orally transmitted texts - that of Thomas Moran and that of the Kenny family - have affinity with the text in the Will Carleton Songster. This helps us understand the lines of tranmission better than we did.