The A4240 begins at the roundabout at theLoughorside of theLoughor bridge.The road heads east through Loughor, then onwards throughGorseinon,where it forms the east–west main road intersecting with the B4296 in central Gorseinon. The A4240 then continues through the Garngoch Industrial Estate and then throughPenllergaerafter which it continues along a single carriageway shared with theA48until it reaches the roundabout which forms Junction 47 with theM4 motorway.[2]
