State Route 123 is a very short highway entirely in Polk County. It serves as a link from State Route 68 to connect with North Carolina Highway 294. This road links Turtletown and Farner in Tennessee to Murphy and Hiwassee Village in North Carolina. The road is also locally known as Saw Mill Road and lies entirely with the Cherokee National Forest.

State Route 123 is not concurrent with any other highways and does not intersect any other highways except at the termini.