Baulkham Hills is a suburb in the Hills District of Greater Western Sydney, in the state of New South Wales, Australia. It is 31 kilometres north-west of the Sydney central business district within the local government area of The Hills Shire, with a small portion south of the M2 Motorway in the City of Parramatta. Baulkham Hills is the administrative seat of The Hills Shire, an outer metropolitan shire within Greater Sydney. The suburb is also the most populous within the Hills Shire. It is known colloquially as “Baulko”.
The land that is now called Baulkham Hills was originally home to the Bidjigal people, who are believed to be a clan of the Darug people, who occupied all the land to the immediate west of Sydney. The best-known Aboriginal person from that time is Pemulwuy, a Bidjigal leader who led the Indigenous resistance movement against the British forces, including sacking farms in Castle Hill, before his eventual capture and execution by the British militia.
The Bidjigal people are today commemorated by Bidjigal Reserve which straddles the suburbs of Castle Hill, Baulkham Hills, North Rocks, and West Pennant Hills.
The first European settler in the Baulkham Hills Shire was William Joyce. In 1794 he was given a grant of 30 acres (121,000 m²) in what became Baulkham Hills. The suburb was largely made up of land grants until the mid 19th century, when many of these started to be subdivided into farms. This was accelerated by the construction of the Rogans Hill Railway Line. Urban developments were expedited from the 1960s. The name Baulkham Hills was given to the area by Andrew McDougall, a settler from Buckholm Hills, County of Roxburgh, Scotland. The name, which reminded McDougall of his homeland, was officially recognised in 1802. Baulkham Hills Post Office opened on 1 April 1856.
On 29 June 2018, a small portion of the Baulkham Hills suburb was proclaimed as part of the new suburb of Norwest.