Hi Leeneia
There are actually a couple called Derry Down, but that aside it isn't a song that is called Derry Down, it's the tune and chorus which have been used for hundreds of songs since about 1685 on both sides of the Atlantic. During the nineteenth century it was mostly to be found in the maritime states of the US and Canada, particularly New York State, and even more particularly in the lumbercamps.

I agree with Jim that is the better known of any of the DD tunes. I just found the 4th line slightly different. Have a listen to MacColl's singing. That is pretty much the tune as printed in about 1700, though there are lots of variations and the further you get from the source both in time and geographically the more diverse they become, as you would expect.

If it helps, the format is always anapaestic tetrameter and the chorus is pretty much recognisable in all its forms, and the leap in the 3rd line is almost always there. I think it's a great tune.

As I stated wayback in the thread the 2 words 'derry' and 'down' have appeared in various combinations since Tudor times and probably earlier, but if the tune is designated 'Derry Down' it has become so famous that most people in history with any musical knowledge would have known what the tune was.

Having said that a great musical historian of the late 19thc mentioned the 2 'Derry Down' tunes and I'd be pleased to be told what the other one is, (other than that you've posted here and sung by Ewan).