Artist: John McCormack
Author: Joseph Campbell
Label: Victor
Year: 1910

Joseph Campbell (Seosamh MacCathmhaoil) was a North Irish song collector (1879-1944) with Irish speaking grandparents. His partner composer Herbert Hughes heard this song first in County Donegal (by someone who knew it from his own father, who in turns learned it half a century before). They've got their own river Lagan there (spilling into Lough Swilly), different from the Belfast Lagan.

Which Lagan this song is about, the river that leads through Belfast or the smaller Lagan flowing through east Donegal and west Tyrone, is irrelevant. According to Sinéad O'Connor it's about Ireland as a whole. The song was written in a time when it was against the law to write favorably about Ireland. So poets and writers referred to the land as if it was a beautiful woman. There's a Lagan in both Ulster and the Irish Republic, that alone makes it political.