The Illawarra Highway runs in an east/west direction from the Hume Highway in the west, 14 kilometres south of Berrima and 44 kilometres north of Marulen, to the Princes Highway in the east at the Illawarra Regional Airport. It is 63 kilometres long and a 1 hour drive. The kilometres mentioned in this website are approximate only.

As the highway crosses over the Macquarie Pass there are many hairpin bends and steep hills to contend with. It is unsuitable for big trucks and other articulated vehicles. For larger vehicles it is advisable to use the Mount Keira Road (Route 88) also known as Picton Road which runs from Wollongong to the Hume Highway.