Blacktown City Council is a local government area in Western Sydney, situated on the Cumberland Plain, approximately 35 kilometres (22 mi) west of the Sydney central business district, in the state of New South Wales, Australia. Established in 1906 as the Blacktown Shire and becoming the Municipality of Blacktown in 1961 before gaining city status in 1979, the City occupies an area of 246.9 square kilometres (95.3 sq mi) and has a population of 410,419, making it the most populous local government area in Sydney.

Greater Western Sydney (GWS) is a large region of the metropolitan area of Greater Sydney, New South Wales (NSW), Australia that generally embraces the north-west, south-west, central-west, far western and the Blue Mountains sub-regions within Sydney's metropolitan area and encompasses 11 local government areas: Blacktown, Blue Mountains, Camden, Campbelltown, Cumberland, Fairfield, Hawkesbury, Liverpool, Parramatta, Penrith and Wollondilly. It includes Western Sydney, which has a number of different definitions, although the one consistently used is the region composed of ten local government authorities, most of which are members of the Western Sydney Regional Organisation of Councils (WSROC). The NSW Government's Office of Western Sydney calls the region "Greater Western Sydney".