Baulkham Hills is a suburb in the Hills District of Greater Sydney, in the state of New South Wales, Australia. It is located within 30 kilometres (19 mi) north-west of the Sydney central business district mostly within the local government area of The Hills Shire, of which Baulkham Hills was formerly the administrative seat and namesake of The Hills Shire. A small section of the suburb which is located south of the Hills Motorway-Windsor Road intersection is part of the City of Parramatta.