County of Middlesex
Place To 31/3/1965
Former county. It became a shire in the 10th century, but most of the area was lost to the County of London with the passing of the Local Government Act of 1888. It officially ceased to exist in 1965 when it was absorbed into Greater London, so presumably, the Hogarth plaque was erected before then. The name however is still widely used in addresses.