O'Connell Road commences at the roundabout with Great Western Highway in Kelso, New South Wales (just east of Bathurst) and heads in a southeasterly direction, crossing the Fish River just north of O'Connell, and continuing southeast until it eventually terminates in Oberon.

It is fully sealed over its entire length and of high enough standard to accommodate B-double trucks.

In conjunction with Goulburn-Oberon Road from Hume Highway to Oberon, this scenic route provides a leisurely and surprisingly direct route between Bathurst and Goulburn.

256 was declared along this road on 8 August 1928, from the intersection with Great Western Highway near Bathurst to Oberon (and continuing southwards via Taralga to the intersection with Hume Highway at Goulburn);[2] with the passing of the Main Roads (Amendment) Act of 1929[5] to provide for additional declarations of State Highways and Trunk Roads, this was amended to Main Road 256 on 8 April 1929.

Under this act, O'Connell Road today is declared part of Main Road 253, from Bathurst to Oberon (and continuing eastwards via the Jenolan Caves and Hampton to the intersection with Great Western Highway at Hartley).