Situated in southwestern Sydney it is located on the boundary of the Fairfield and Canterbury-Bankstown local government areas.

While working on the Legislative Council Chambers in Macquarie Street, Sydney, Lennox met the Surveyor-General, Thomas Mitchell.

[5] The Surveyor-General lost little time in submitting Lennox's credentials to the Governor of NSW Sir Richard Bourke, describing him as "a very well qualified person recently arrived in the Colony."

Acting on Mitchell's recommendation, Bourke provisionally appointed Lennox as a Sub-Inspector of Bridges at a salary of £120 ($240) per annum.

[9] The Hawkesbury sandstone used in building the bridge was quarried on the bank of George's River at present day East Hills, 11 kilometres (6.8 mi) from the proposed site of the bridge, allowing workers to row a punt to transport the stone to the construction site.

[5] The bridge was constructed entirely by unskilled convicts, despite Lennox's numerous requests to Mitchell for skilled labourers.

Retribution at Liverpool Court was swift and savage; those who were spared the chain gang received up to fifty lashes of the "cat".

Lennox made arrangements to obtain a duplicate plate but the original was found and restored to the bridge.

Upon being advised that the bridge was nearing completion, Governor Bourke selected 26 January 1836 for the official opening date, as this coincided with the 48th anniversary of the colony's foundation.

Lansdowne Bridge is considered to be one of the finest examples of colonial architecture in Australia as well as David Lennox's masterpiece of design.

[5][14] The place is important in demonstrating aesthetic characteristics and/or a high degree of creative or technical achievement in New South Wales.