The best-known Aboriginal person from that time is Pemulwuy, a Bidjigal leader who led the resistance movement against settlers during the Hawkesbury and Nepean Wars, including sacking farms in Castle Hill, before his eventual capture and killing by bounty hunter Henry Hacking.

As Governor he needed to find new country for settlement and farming land for crops so as to feed a struggling infant colony.

[citation needed] The majority of the convicts who worked the prison farm were Irish Catholics, many having been transported for seditious activity in 1798.

[citation needed] The first free settler in Castle Hill, a Frenchman Baron Verincourt de Clambe, in unusual circumstances received a grant of 200 acres (81 ha) in 1802.

It has been suggested that locals of the time commonly referred to de Clambe's house ("The Hermitage")[6] as "The Castle" because of the Baron's noble status.

As Sydney expanded, the orchards disappeared and were replaced with a sprawl of suburban dwellings, retail and commercial establishments and light industry.

[1] Castle Hill's commercial area centres on a section of the Old Northern Road at the suburb's eastern side.

A new library and community centre, with a unit apartment building on its upper floors, opened next to Castle Towers in 2004.

To the north of Showground Road lies suburban, with approximately 1000 homes, the Samuel Gilbert Public School, Castle Glen Oval and the Knightsbridge Shopping Court.

The bulk of Castle Hill residents own private vehicles and travel to work using these, however bus services and the Sydney Metro Northwest run to the suburb.

Major works were undertaken in 1922 to convert the line into a railway, and trains began servicing Castle Hill on 28 January 1923.

As a cost-cutting measure, the state Labor government of Jack Lang closed the line on 31 January 1932, amid much public protest.

[18] Several proposals existed for another rail line to Castle Hill, resulting in the Sydney Metro Northwest beginning construction on 18 June 2014.

Opened in late 1988 and under the ownership of The Hills Shire Council it was one of the largest venues of this type in New South Wales until it was demolished in 2013 to make way for the Sydney Metro Northwest.

The Museums Discovery Centre is an off-site visible storage and collection care facility, located on the corner of Windsor and Showground roads in Castle Hill.

It has a unique and diverse collection of 400,000 objects spanning history, science, technology, design, industry, decorative arts, music, transport and space exploration.