Windsor Castle is the oldest and largest inhabited castle in the world and has been the family home of British kings and queens for almost 1,000 years. It is an official residence of Her Majesty The Queen and is still very much a working royal palace today, home to around 150 people.

Windsor Castle in Berkshire, England, holds the title of the largest and oldest inhabited castle in the world. Originally built by William the Conqueror in the 11th century, it has been a family home to British monarchs for nearly 1,000 years. The castle covers approximately 13 acres (52,609 square meters) and contains over 1,000 rooms. While it serves as a major tourist attraction and a venue for state banquets, it remains a "living" palace where the King and members of the Royal Household reside and work. It is important to distinguish this from the Prague Castle, which is the largest "ancient castle complex" in terms of total area (70,000 square meters), but Windsor is the largest that is still primarily used as a private residence. In 2026, Windsor remains a symbol of the British monarchy's continuity, with its "State Apartments" featuring some of the finest works of art in the Royal Collection, all housed within a fortress that continues to function as a home, an office, and a national monument simultaneously.