1) Area of London 
Hillingdon is a suburban area within the London Borough of Hillingdon, situated 14.2 miles (22.8 km) west of Charing Cross. It was an ancient parish in the county of Middlesex that originally included the market town of Uxbridge. During the 1920s Hillingdon experienced a rapid increase in population and was absorbed by Uxbridge Urban District in 1...
outer borough of London, forming part of its western perimeter. Hillingdon belongs to the historic county of Middlesex. Hillingdon was created a ...
a borough of Greater London, England. 232,200.