It goes east as a 4-lane, changing to a 6-lane, divided highway called Sam Ridley Parkway, a major thoroughfare featuring numerous strip malls, apartments, a high school, and a hospital.

The highway then narrows to 2-lanes and crosses a bridge over the Stones River just south of Percy Priest Lake, where it leaves Smyrna.

SR 266 continues north through industrial areas before entering downtown at an intersection with Tennessee Boulevard, where it becomes S College Street.

For most of its length through Smyrna, Route 266 is a 4-lane, now changing to a 6-lane, highway called Sam Ridley Parkway, named for the mayor of the city from 1947 to 1987.

(Sam Ridley was forced to resign in 1987 due to a conflict-of-interest suit; as a testament to his popularity, his identical twin brother Knox was promptly instated as mayor.