Hard to believe this isn't in the DT database. I've copied the lyrics below from those posted on the forum by The Walrus, back in 2001.

I recall a story that Bonnie Prince Charlie, long after Culloden, heard some exiles singing this, and he burst into tears. Probably a legend, but my kind of legend.

Lochaber is a region around Fort William, in the Highlands of Scotland. It includes Moidart, when Prince Charlie landed; Glenfinnan, where he rallied supporters of his father's claim to kingship; Glencoe; and the 'small isles' of Eigg, Rum, Muck, and Canna.

Here's a link to another version of the lyrics, along with a midi and some background:
http://www.contemplator.com/scotland/lochaber.html

FAREWELL TO LOCHABER

Farewell to Lochaber and farewell, my Jean,
Where heartsome with thee, I habe many days been,
For Lochaber no more, Lochaber no more,
We'll maybe return to Lochaber no more.
These tears that I shed, they are all for my dear,
And no' for the dangers attending on war,
Though borne on rough seas to a far bloody shore,
Maybe to return to Lochaber no more.

Though hurricanes rise and rise every wind
They'll ne'er make a tempest like that in my mind.
Though loudest of thunder on louder waves roar,
There's nothing like leaving my love on the shore.
To leave thee behind me, my heart is sair pained,
By ease that's inglorious no fame can be gained,
And beauty and love's the reward of the brave,
And I must deserve it before I can crave,

Then glory, my Jean, maun plead my excuse,
Since honour commands me, how can I refuse?
For without it I ne'er can have merit for thee,
And without thy favour I'd better not be.
I gae then, my lass, tae win honour and fame,
And if I should luck to come gloriously hame,
A heart I will bring thee with love running o'er,
And then I'll leave thee and Lochaber no more.