It isn't in a county. Greater London is its own administrative area.
London is in London ....
London is not a central county in England, it is in the South East of the country. Central London is not a county, but is within the county of Greater London.
Cricklewood, the suburb of London, is in the county of Middlesex, England.
Kent is a county in southeast England adjoining London.
North Yorkshire (by area) or Greater London (by population)
London is a part of Greater London county. UK does not have states or provinces, however, instead we have county.
Norfolk is a county about 100 miles northeast of London.
Hertfordshire is the county just north of London.
Suffolk is not in London. Suffolk is a county found in the East of England to the North East of London.
The Tower of London is in Greater London and not in any particular county unless you mean 'country', in which case it is in England, which is part of the United Kingdom.
Camberley is in England in the county of Surrey, just outside London.
Woolwich is in South East London, England.