For an Expatriot Canadian, it is Joni Mitchel's "If I had a River." or Lucie Blue Tremblay's "Tour Song", or of course, Un Canadien Errant".

For a pure poetic discription of a single aspect of Canada, "Let Me Fish off Cape St. Mary's is good. I grew up 100 miles from Cape St. Mary's. But INMHO, 'Mon Pays' by Gilles Vigneault (1965) is better.