The area is north-west of the Sydney central business district, and encompasses 401 square kilometres (155 sq mi) stretching from the M2 Hills Motorway in the south to Wisemans Ferry on the Hawkesbury River in the north.

[1] The current mayor of The Hills Shire is Dr Michelle Byrne (Liberal), who was elected on 14 September 2024.

[4] The median weekly income for residents within The Hills Shire was approximately 150% higher than the national average.

The Hills Shire started developing gradually with its new road systems and farming as more Europeans settled here.

[16] The second proposed a merger of parts of Parramatta, Auburn, The Hills, Hornsby, and Holroyd to form a new council with an area of 82 square kilometres (32 sq mi) and support a population of approximately 215,725.

[17] Following an independent review, on 12 May 2016 the Minister for Local Government announced that the merger of parts of The Hills Shire suburbs south of the M2 Motorway (North Rocks, Northmead and part of Baulkham Hills) with the City of Parramatta to form a revised City of Parramatta Council, with immediate effect.

[3] In June 2020, Councillor Brooke Collins made national news for controversially objecting to the Welcome to Country, reportedly stating "How do you know they didn’t wipe out another race when they arrived here 70,000 years ago?".