Illinois State Route 123 runs north-south for aprox. one (1) mile in Sangamon County. IL St Rt 123 does not pass through any towns in Western Sangamon County. IL St Rt 123 is not multi-plexed in Sanamon County. IL St Rt 123 intersects the following highway in Sangamon County. Illinois State Route 125, near Pleasant Plains.
WB IL St Rt 123 at the Sangamon/Menard County Line. WB IL St Rt 123 at the Menard/Sanagmon County Line. Sangamon County mile marker at the Menard/Sangamon County Line. WB IL Rt 123 near Sparrow Road. A junction marker on EB IL St Rt 125. The western end of IL St Rt 123. Two views of the western end marker. The western end of IL St Rt 123. (July, 2009) The western end marker. (July, 2009) The western end of IL St Rt 123. (July, 2017) The western end marker. (July, 2017)
