The ancient royal residence in Berkshire - said to be the monarch's favourite home - is where the Queen chose to celebrate her 90th birthday on April 21.
See also: Ten British castles you can rent for holidays
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Continuously lived in for almost 1,000 years, it is far removed from the military base William the Conqueror had built on high ground to defend the western approach to London.
It has been transformed over the centuries by a string of monarchs into an archetypal romantic royal palace with turrets, towers, battlements and lavish apartments, in a picturesque setting overlooking the River Thames.
Windsor Castle is not only the Queen's haven where she spends most weekends, but the setting for some of her public duties, like hosting investiture ceremonies and welcoming visiting foreign heads of state.
The royal residence topped a poll commissioned by TV on-demand service UKTV Play to launch The Castle Collection - a selection of programmes celebrating a range of shows featuring castles, from Time Team to The Secret Lives Of The Tudors.
Windsor was followed in the nation's affections by Bodiam Castle (above), with Edinburgh Castle third. Next was Warwick Castle, Dover Castle was fifth and sixth was Alnwick Castle - used as a location in some of the Harry Potter films.
When a small girl, Royal Lodge in Windsor Great Park was the country retreat of the Queen, then Princess Elizabeth, her sister Princess Margaret and their parents the Duke and Duchess of York. Later the royal sisters spent their war years living at the castle for safety.
Emma Boston, general manager of UKTV Play, said: "We are a nation of castle lovers and there are an incredible array of beautiful historical ancient treasures across the country.
"When we looked at the shows that proved really popular on the service we found that those set in or featuring castles often did really well.
"So we created the Castle Collection on UTKV Play, where you can find fantastic historical programming such as Time Team, Secrets Of Britain and Castle Builders - as well as the surprising, such as an episode of paranormal show Ghost Adventures set in a castle."
The 10 best-loved British Castles:
1 Windsor Castle
2. Bodiam Castle
3. Edinburgh Castle
4. Warwick Castle
5 Dover Castle
6 Alnwick Castle
7 Leeds Castle
8. Caernarfon Castle
9. Bamburgh Castle
10. Stirling Castle