|Distance:||3 miles (4.8 km)|
|Meets:||B4603, A4067, M4, A48, B4625, A4230|
|Route outline (key)|
The B4291 is a short B-road on the eastern edge of Swansea.
Starting at a mini-roundabout on the B4603 (former A4067) by the Mond nickel works in Clydach, the road heads at first southeastward to cross the A4067 bypass at a roundabout immediately before crossing the River Tawe by a single-arch bridge and entering the village of Glais.
Continuing south through Glais the road gradually climbs a hillside (with views of the Swansea Valley to the right) to reach Birchgrove and then Lôn-las, where traffic lights mark the start of a short spur leading off to the right to junction 44 of the M4.