When SR 135 Conn. ends at US 23/SR 19, US 221 Truck/SR 135 Truck turn left onto the US 23/SR 19 concurrency known as Larry Contos Boulevard, and then turns left onto US 341/SR 27 (Golden Isles Parkway) eventually terminating at northbound US 221.

It directs truck drivers away from the local streets of Laurens, along the entire length of SC 127 and part of US 76.

It was established in 1941 when mainline US 221 was realigned further west along a straight route between Chesnee and Rutherfordton.

It follows the old US 221 alignment before it was rerouted onto Marion Bypass, located west of the city.

It avoids an 18-mile (29 km) drive of endless curves and constant elevation changes along a stretch of US 221 between Linville and Blowing Rock, dubbed the Little Parkway Scenic Byway.