The singer is far away from home. He bids adieu to the places he spent his youth, describing their beauty. He would return to see them all.
Notes to IRHardySons: "Garrison is in the north of Fermanagh, on the shores of Lough Melvin, just on the border with Co Leitrim."
The places named that I can find are all in Northern Ireland or northern Eire: in Co Fermanagh (Aghamuldowney, Farrancassidy, Lough Erne, Lough Melvin), Co Donegal (Belleek, Camlin Groves, Bundoran, Ballyshannon), Co Leitrim (Kiltyclogher), Co Down (Kilcoo) and Co Louth (Carranmore). The remaining names are Brolagh Bog, Sheehan Mountain and Knockareven. - BS