The Cahill Expressway starts at the interchange with the Bradfield Highway and heads east as a four-lane road on the upper level of a two-level viaduct across the northern edge of the Sydney CBD at Circular Quay, before turning south at the interchange with the Sydney Harbour Tunnel and then southeast into the 371-metre (1,217 ft) Domain Tunnel, located underneath the Royal Botanic Garden.

[4] It emerges soon afterwards in a cutting, then enters another tunnel under The Domain, before ending at the interchange with Cowper Wharf Road and continuing south as the Eastern Distributor.

Entry ramps for the northwestern end of the Cahill Expressway also exist heading southbound along parts of the Warringah Freeway in North Sydney and the Bradfield Highway across the Harbour Bridge.

The Roads & Traffic Authority offers tickets to view the New Year's Eve fireworks from the Cahill Expressway deck through a competition.

[5] Former The Sydney Morning Herald writer Elizabeth Farrelly described the freeway as 'doggedly symmetrical, profoundly deadpan, severing the city from the water on a permanent basis'.

Demolition of the elevated section of the expressway has been proposed, most prominently by former Australian Prime Minister Paul Keating, who in 1994 offered federal funds in the amount of A$150 million toward such a project.

[17] The Cahill Expressway was signedposted as part National Route 1 from its southeastern end to the interchange with the Sydney Harbour Tunnel, when the latter opened in 1992; this was replaced with Metroad 1 in 1993.

The painting shows a stylised view of the Cahill Expressway tunnel and approach road, with a single man shown at the side of the image.