Find the best Entrance - Windsor Castle entrance tickets at Windsor Castle, Windsor. Windsor Castle, the largest and oldest occupied castle in the world, is one of the official residences of Her Majesty The Queen. The Castle's dramatic site encapsulates 900 years of British history. It covers an area of 26 acres and contains, as well as a royal palace, a magnificent chapel and the homes and workplaces of a large number of people. The magnificent State Apartments are furnished with some of the finest works of art from the Royal Collection, including paintings by Rembrandt, Rubens, Canaletto and Gainsborough.