TheAfon Dulas, orNorth Dulas, is ariver forming the border betweenMerionethshire/Gwynedd andMontgomeryshire/Powys inWales. Another river called Afon Dulas joins the Dyfi from the south, upstream of itsconfluence with the North Dulas: locally this is referred to as theSouth Dulas.
Afon Dulas rises from a source in the hills aboveAberllefenni and passes throughCorris,Esgairgeiliog andPantperthog before joining theAfon Dyfi atFfridd Gate nearMachynlleth.[1]
The Dulas is recorded as an important land boundary in 1200, in a document written in 1428. This document describes the land owned by Einion ap Seisyllt, in the time ofLlywelyn the Great, as "tota terra inter aquas de Dyfi et Delwas" (Latin, meaning: all the land between the rivers Dyfi and Dulas).[2]
It rises in Glaslyn, below the slopes ofFoel Fadian, and passes thehamlet ofForge andPlas Dolguog before joining the Dyfi.
Close to its confluence with the Dyfi it is crossed by theCambrian rail line on a bridge known as the Black Bridge. After the line had been repeatedly closed due to flooding after heavy rain, in 2021 it was announced that the bridge and its approaches were to be raised by a metre to try and alleviate the problem.[5] Work began on 15 May and was due to be completed by 28 June.
52°36′00″N3°50′30″W / 52.6001°N 3.8418°W /52.6001; -3.8418