Singer's intended lives with her rich parents by the Avonmore river. She would marry him "without riches or no earthly store." They meet in Glandore. He dreams of their marriage. They would sail away, if necessary. Until then he won't reveal her name.
Munnelly/Deasy-Lenihan translates the title, which is also the last line of all but the last verse, as "For Ireland I will not tell whom she is." "... some versions of the song carried intimations of carnality." The song is classified as a reverdie. "The classification refers to the greenwood setting in which the poet encounters the beautiful maiden much as in an aisling" [except that this is not a vision song]. See the notes to "Eileen McMahon" and references there for a discussion of aisling. [Also the notes to "Granuaile." - RBW]
The Avonmore River flows through County Wicklow. Glandore is in County Cork. Maybe that's part of the code.
There is a Gaelic version with translation at "An Eirinn Ni Neosainn Ce Hi" at the Makem site. The story is less detailed than Munnelly/Deasy-Lenihan 14.
Munnelly/Deasy-Lenihan: "The Clare Gaelic scholar Eugene O'Curry stated that this song was written originally about 1810 .... The song in English which Tom sings has been about for a good many years likewise, as is witnessed by the similar version which Freeman noted down in London in 1915...."
Reverdie: "a song-type in which the poet is approached, in pastoral surroundings, by a beautiful otherworldly woman who symbolizes spring and Love....[It is] an old French poetic form pre-dating the political aisling form used in 18th century Irish poetry. French influence on Irish poetry took place during the Middles Ages when Norman-French families were granted estates in Ireland by the English crown." (source: Michael Robinson, "Danny Boy -- The Mystery Returns! , or, The Young Man's Dream" at The Standing Stones site. The article gives a clear example of the form with a reference to "A Young Man's Dream" and information on the form from Bruce Olson). While there are countless non-political Irish songs in which a young man meets a beautiful woman, the essential element of a reverdie is that the meeting must take place in a dream. - BS