It rises north of the village of Llandybie and flows southwards through that village and joins the Loughor on the northwestern edge of Ammanford near Aberlash Mill .
The Afon Marlas is a right - bank tributary of the River Loughor in eastern Carmarthenshire , West Wales .
Afon Marlas rises north of the village of Llandybie and flows southwards through that village and joins the River Loughor on the northwestern edge of Ammanford near Aberlash Mill .
The Afon Marlas is a right - bank tributary of the River Loughor in eastern Carmarthenshire , West Wales .