The London Borough of Hillingdon is the westernmost borough in Greater London, England which had a population of 273,936 according to the 2011 Census. It was formed from the districts of Hayes and Harlington, Ruislip-Northwood, Uxbridge, and Yiewsley and West Drayton in the historic county of Middlesex. Today, Hillingdon is home to Heathrow Airport and Brunel University, and is the second largest of the 32 London boroughs by area.