The road links the suburb of Wahroonga in the northeast, to the major central business district of Parramatta in the southwest.

[5] Pennant Hills Road commences at Pearce's Corner, the intersection with Pacific Highway in Wahroonga, and heads in a southwesterly direction as a dual-carriageway, four-lane road, crossing an intersection with exits leading to the southern end of Pacific Motorway (M1) and the northern end of NorthConnex nearly immediately and widening to a six-lane road, then passes through the Hornsby Shire suburbs of Normanhurst, Thornleigh and Pennant Hills.

This also means that southbound traffic already on Pennant Hills Road rarely has to stop at the Thompson's Corner intersection, only if pedestrians are crossing.

It was surveyed by government surveyor James Meehan in order to provide a route from Ermington Wharf to the Pennant Hills sawmill established by Governor Lachlan Macquarie in 1816.

[10] State Highway 13 eventually assumed the role of a western bypass of Sydney, made official when it was declared as part of Ring Road 5 in 1964.

With the declaration of Pennant Hills Road as part of Cumberland Highway, State Route 55 was replaced with State Route 77, from Pearce's Corner to the interchange with James Ruse Drive, in 1988 (with the remaining southwestern section into Parrramatta now unallocated); it was replaced with Metroad 7 in 1993.

With the conversion to the newer alphanumeric system in 2013, Pennant Hills Road was re-designated part of route A28, replacing the last remnant of Metroads 6 and 7 along it.

The average traffic flow on Pennant Hills Rd, according to a 2002 survey by the RTA, was 62,656, with the busiest area occurring around Thompsons Corner.

Opened on 31 October 2020, NorthConnex will help alleviate traffic travelling between Western Sydney and the Central Coast.