The Sovereign also holds the title Duke of Lancaster, regardless of gender. Who does this title currently describe?
Alan Reid (courtier):  The Sovereign also holds the title of Duke of Lancaster (regardless of gender), which brings with it responsibility for the Duchy of Lancaster estates. Duke of Lancaster: The Duke of Lancaster is an ancient title which is informally used within Lancaster to describe Elizabeth II, the monarch of the United Kingdom and owner of the estates of the Duchy of Lancaster.
Elizabeth II