Mid-Western Highway forms part of the most direct route road link between Sydney and Adelaide,[4][5] with its eastern terminus in Bathurst and western terminus in Hay.

[6] Mid-Western Highway runs generally west–east, roughly aligned along the Lachlan River in New South Wales, then stretching across the Hay Plain, generally towards the south-western corner of New South Wales.

From Mardsen to West Wyalong, Newell Highway is concurrently signed as routes A39 and B64.

The highway was rerouted between Gunbar and Balranald to pass through Hay on 24 September 1929.

[16] Mid-Western Highway was signed National Route 24 across its entire length in 1955.