Except in very rare cases, mitochondrial DNA is inherited only from your mother. She got it from her mother, who in turn got it from her mother, and so on. When you're charting your maternal pedigree, then, that is precisely the line you are charting: yourself, your mother, your mother's mother, etc. Likewise, when it comes to identifying maternal country of origin it would be the furthest back known origins for that same line of women. For instance, if your maternal grandmother's father immigrated from Freedonia in the late 1800's, that is not your maternal country of origin – rather, your maternal origins would in fact be where your grandmother's mother immigrated from (in this specific case, Freedonia's neighbor country Sylvania).