The name Hornsby is derived from convict-turned-constable Samuel Henry Horne, who took part in the apprehension of bushrangers Dalton and MacNamara on 22 June 1830.

[6] Residential growth in the area was left to private developers, who acquired land both east and west of the railway station.

Having acquired a property in Rosemead Road, the Roberts family built "Mount Errington", a spectacular mansion in the Arts and Crafts style, now heritage-listed.

In the years following World War II, Hornsby saw rapid suburbanisation and population growth, driven by Sydney's expanding suburban development.

This transformation was part of the broader trend in Sydney, where suburban sprawl increased as people moved out of the crowded city centre.

Its transport infrastructure also improved and the development of the rail network played a key role, with Hornsby station becoming a major interchange for commuters travelling to Sydney.

The area retains its significant natural beauty, in closeness to the nearby Ku-ring-gai Chase National Park.

Hornsby railway station is the junction of the T1 North Shore and the T9 Northern Line of the Sydney Trains network and is a hub for some services and is connected via bridge to Westfield.

The completion of the Pacific Motorway (M1), which has its southern end at the neighbouring suburb of Wahroonga, means that the heavy traffic now bypasses the already busy Hornsby town area.

[17] In October 2020, the northernmost section of the NorthConnex tunnel also located in close proximity to Hornsby in the neighbouring suburb of Wahroonga was opened.

On the eastern side of the highway from south to north are the police station, the court house[18] and the historic Hornsby Shire Council chamber (built in two stages in 1915 and 1930).

The north-western side of the suburb is occupied by various industries and the northern end of Hornsby features a major railway workshop.

Many of the residential areas on the western side of the train line enjoy bushy surrounds and close proximity to Regional and National Parks, as well as the beautiful Lisgar Gardens.

In recent years, high-rise apartments have been constructed adjacent to the train line as part of the NSW state planning policies to allow medium to high density development along transport corridors.

Hornsby Aquatic Centre, which was built in 1962, had reached the end of its safe working life, and was closed on Friday 24 December 2010.

After David's death, subsequent owners preserved the garden, until Hornsby Shire Council acquired the entire property in 1999, adding the grounds (as Neal Park) to its Bushcare program.

[22] That same year, the entire property was added to the New South Wales State Heritage Register, listed as Edgeworth David's House and Grounds.

In 1920, Cotton purchased land from his brother Leo and began developing the gardens for his own interest and satisfaction.

Aided by friends and family, he created extensive gardens and fishponds on the natural bushland that sloped down from Lisgar Road.

Cotton became friends with Professor Eben Gowrie Waterhouse—owner of Eryldene in the suburb of Gordon—and the two spent much time together, sharing an interest in camellias.

[25] This park is located in Valley Road and is named after Ginger Meggs, a comic-strip character created by the Australian cartoonist Jimmy Bancks.

Bancks spent much time in the area around this park during his childhood, so Hornsby Council named it after his famous character Ginger Meggs.