It meets Cumberland Highway at the intersection of Hart Drive in Constitution Hill and continues in a southeasterly direction as part of Cumberland Highway, before meeting and merging into Briens Road at an intersection in Northmead; Cumberland Highway continues east along Briens Road.

The North-West T-way runs alongside the entire length of Old Windsor Road.

[4] This was the second main road built for the colony of Sydney to connect Parramatta and Windsor—a distance of 23 miles and 16 chains (37.33 km).

[9] In 2007, the intersection with Norwest Boulevard at Bella Vista was upgraded into an interchange to allow an underpass for Old Windsor Road.

[11] As part of Cumberland Highway, the section between Constitution Hill and its southeastern end at Northmead was allocated State Route 77 in 1988, replaced by Metroad 7 in 1993; Metroad 7 was removed when Westlink M7 opened in 2005.