Visited 5.6.2010. After a stop-off at Waun Leuci stone setting, this barrow was an unexpected extra (it's not on the OS) on the way along the Tawe valley towards Cerrig Duon. It looks pretty intact and is in a slightly unusual valley bottom location - although it's still at 400m above sea level, so hardly "lowland".
From here the Tawe can be crossed fairly easily on the approach to Maen Mawr.
Possible round barrow next to the Tawe river. Description from Coflein:
"Located between valley road and river, and 55m south of a monolith, is a stony mound. It measures 5m (NW-SE) by 4m and 0.4m high. It seems undisturbed. Given its relative proximity to various stone settings, its identity as a burial cairn is distinctly possible. However, stone clearance and platform features have been identified to the south of this site."