While the term "castle" is often used loosely, there are a few official royal residences that could be considered castles:
* Windsor Castle: This is the oldest and largest inhabited castle in the world, and Queen Elizabeth II used it as a weekend retreat and for official engagements.
* Edinburgh Castle: Located in Scotland, this castle is a UNESCO World Heritage Site and has been a royal residence for centuries. However, the Queen used it mostly for official visits.
* Caernarfon Castle: Located in Wales, this castle is another UNESCO World Heritage Site and was the site of Prince Charles's investiture as Prince of Wales.
However, it's important to note:
* Buckingham Palace is a royal residence but not technically a castle.
* Balmoral Castle and Sandringham House are also not castles, although they are important royal estates.
Therefore, there is no definitive answer to the question of how many castles Queen Elizabeth had. While she had access to multiple historic residences, none of them were her personal property.