Corsica
"Dio vi Salve Regina" (Hymn to the Virgin Mary)
Words by: Francesco de Geronimo
Music by: Adhémar de Monteil
Adopted: 1735
Corsica is a French island in the Mediterranean and a province of France (as such the French anthem is the official anthem). On January 30, 1735, it became an independent country and adopted "Dio vi Salve Regina" as its anthem (interestingly, several decades before France adopted its current anthem!) When Corsica was made a part of France roughly 30 years later, the anthem remained as an unofficial regional anthem (France, not being a federalist country, does not have official anthems for its regions.)
Special thanks to: Ben Cahoon for informing me about this anthem, Paweł Ciupak for the music file and James Mercier for some of this information.
See also: France.