Castlereagh is a suburb of Sydney, in the state of
New South Wales, Australia. Castlereagh is 67
kilometres west of the Sydney central business
district, in the local government area of the City
of Penrith and is part of the Greater Western
Sydney region.

The rich river flats in the Castlereagh locality still
provide for a thriving agricultural industry along
the Nepean River.
Castlereagh Road is one of the important
transport link in Sydney connecting the
Hawkesbury and Penrith regions.