The following are the monarchs who have reigned longest in the United Kingdom of Great Britain and Ireland (Northern Ireland after 1922), the Kingdom of Great Britain, the Kingdom of England, or the Kingdom of Scotland since AD 1000.
- Victoria of the United Kingdom:
- 63 years, 7 months, and 3 days (June 20, 1837 – January 22, 1901)
- George III of the United Kingdom:
- 59 years, 3 months, and 4 days (October 25, 1760 – January 29, 1820)
- James VI of Scotland (and I of England):
- 57 years, 8 months, and 3 days (July 24, 1567 – March 27 1625)
- (22 years, and 3 days in England (March 24, 1603 – March 27 1625))
- Henry III of England:
- 56 years, 28/29 days (October 18 or 19, 1216 – November 16, 1272)
- Elizabeth II of the United Kingdom:
- 54 years, 5 months and 10 days as of July 16, 2006 (February 6, 1952 – )
- Edward III of England:
- 50 years, 4 months, and 27 days (January 25, 1327 – June 21, 1377)
- William I of Scotland:
- 49 years (December 9, 1165 – December 4, 1214)
- Elizabeth I of England:
- 44 years (November 17, 1558 – March 24, 1603)
- David II of Scotland:
- 41 years (June 7, 1329 – February 22, 1371)
- Henry VI of England:
- 38 years (August 31, 1422 – March 4 1461 and October 31, 1470 – April 11, 1471)
- Henry VIII of England:
- 37 years (April 22, 1509 – January 28, 1547)
- Alexander III of Scotland:
- 36 years (July 6, 1249 – March 19, 1286)
- Malcolm III of Scotland:
- 35 years (March 17, 1058 – November 13, 1093)
- Henry I of England:
- 35 years (August 3, 1100 – December 1, 1135)
- Henry II of England:
- 34 years (October 25, 1154 – July 6, 1189)
- Edward I of England:
- 34 years (November 20, 1272 – July 7, 1307)
- Alexander II of Scotland:
- 34 years (December 4, 1214 – July 6, 1249)
The current monarch
Should
Queen Elizabeth II still be reigning by:
British monarchy | Lists of people by time in office