- Who
- Queen Margrethe II
- What
- 50 yrs and 297 days year(s):day(s)
- Where
- Denmark ()
- When
Queen Margrethe II ( born 16 April 1940 ) and is 82 yrs old and 146 days ( on the 9th of September) took the throne on the 14th of January 1972 after her father died Frederick IX of Denmark on the 14th January 1972. She has reigned Denmark for 50 yrs and 297 day on the 10th of October.
Queen Margrethe of Denmark Is Now Europe's Only Ruling Female Monarch (people.com)