Cadogan Estates Ltd is a property management company owned by the Earls Cadogan, one of the richest families in the United Kingdom, which also holds the title Viscount Chelsea, used as a courtesy title by the Earl's eldest son. It is the main landlord in the west London districts of Chelsea and Knightsbridge, and is now the second largest of the surviving aristocratic freehold estates in central London, after the Duke of Westminster's Grosvenor Estate, to which it is adjacent, covering Mayfair and Belgravia.