The County of London did not cover all of today's Greater London, and did not have authority over the City of London. It covered the area that the Metropolitan Board of Works (which had run London's roads, bridge, etc) had covered, specifically parts of Middlesex, Surrey and Kent. The LCC had its headquarters at County Hall.

In 1899, after its creation, the county was split into 28 metropolitan boroughs.

City of London (not a metropolitan borough)
Westminster Holborn Finsbury Shoreditch Bethnal Green Stepney Bermondsey Southwark Camberwell Deptford Lewisham Woolwich Greenwich Poplar	Hackney Stoke Newington Islington St Pancras Hampstead St Marylebone Paddington Kensington Hammersmith Fulham Wandsworth Lambeth Battersea Chelsea