SH 342 begins  at a junction with US 77 in Red Oak. It heads north from this junction to two other intersections in Red Oak, FM 2377 (locally known as Louise Ritter Boulevard) and FM 664 (locally known as Ovilla Road).
State Highway 342 originates at a junction with US 77 in the town of Red Oak. It then travels north through the town to two other key intersections, FM 2377 (commonly referred to as Louise Ritter Boulevard) and FM 664 (known locally as Ovilla Road).