The Third Government Farm is a heritage-listed garden at Gilbert Road, near Old Northern Road, Castle Hill, The Hills Shire, New South Wales, Australia. It was built during 1801. It is also known as Castle Hill Heritage Park; Third Government Farm (former); Castle Hill Settlement Site; Old Government Farm Site; Castle Hill Convict Farm; Castle Hill Historic Site. The property is owned by The Hills Shire Council. It was added to the New South Wales State Heritage Register on 22 December 2000.