Many of the most famous residences of the British Monarchy are in fact owned by the state, such as Buckingham Palace and the Palace of Holyrood House. These fulfil the role of the official residences of the Queen and the Royal Family in various areas of the UK.
Other residences, such as Balmoral Castle (Scotland) and Sandringham (East Anglia) are private residences owned by the Queen. Their estates are used to generate a private income for the monarchy, although this is now subject to UK tax.
There is another category of buildings, those run by the charity Historical Royal Palaces. These are former residences of the monarchy, which are still owned by the Queen on behalf of the nation. They include many famous British tourist attractions such as Hampton Court Palace, the Tower of London, Kew Palace and Kensington Palace. There are also hundreds of smaller buildings and hoes which the monarchy own. Many of these are no larger than cottages, and may be sold by the Crown Estates. However, buildings of national significance, such as the palaces, cannot be sold.