Hornsby Heights is a suburb of northern Sydney, in the state of New South Wales, Australia. Hornsby Heights is located 27 kilometres north-west of the Sydney central business district, in the local government area of Hornsby Shire and is part of the North Sydney region.
Hornsby Heights lies to the north of Hornsby. The suburb's northern boundary and western boundary are defined by Berowra Creek, as far south as Galston Road. South of Galston Road, the western boundary, falls generally west of Berowra Creek. Walls Gully forms the eastern boundary. The southern boundary of Hornsby Heights is north of the Hookhams Corner locality. The following localities are in Hornsby Heights: Black Ash, Outlook, Galston Gorge, Montview, Somerville, Rofe Park.