It isn't in a county. Greater London is its own administrative area but is surrounded by the counties of Kent, Surrey, Berkshire, Buckinghamshire, Hertfordshire and Essex. M … iddlesex after the reorganisation. Middlesex BEFORE the reorganisation.Middlesex is now only a postal address.he City of London is the name of an area of London, where the stock markets are etc. London is a city, but the actual City of London is an area between East and Central Lon … don. The City of London is only one square mile that formed the original city in Roman times.