Malltraeth (origin: Mall (corrupt, blasted, desolate, + Traeth (beach))) is a small village in the southwest of Anglesey, in the community of Bodorgan.

[1] After several abortive attempts, a 1 kilometre (0.62 mi) long 'cob' or dyke was completed across it during the 19th century, allowing land reclamation behind it.

Coal mining occurred for a time in the underlying Carboniferous rock strata and the subsidence of these workings resulted in the lakes "Llynnau Gwaith-glo".

'Clwt Glas' (Green Patch) was an area of land at the lower end of Malltraeth and was essentially the reverse side of a mound built as part of the scheme to reclaim the Cefni Marsh (Cors Ddyga) during the latter years of the 18th Century.

The marsh is a Site of Special Scientific Interest and is particularly renowned for its bird life, beautifully captured in Charles Tunnicliffe's paintings, which form the resident gallery at Oriel Ynys Môn, near Llangefni.