Cantref Llŷn

{{Short description|Welsh medieval cantref}}

{{Use dmy dates|date=April 2022}}

Llŷn was an ancient Welsh cantref in north-west Wales. It was part of the kingdom of GwyneddCarpenter, David A. (2003). The struggle for mastery: Britain, 1066–1284. Oxford University Press. p. 364. {{ISBN|0195220005}} for much of its history until it was included in the new county of Caernarfonshire, together with Arfon and Arllechwedd under the terms of the Statute of Rhuddlan in 1284.

Trahain Goch ap Madoc, died 1325, was described as "of Llŷn".{{cite book|last=Glenn|first=T.A.|year=1896|title=Merion in the Welsh Tract: With Sketches of the Townships of Haverford and Radnor : Historical and Genealogical Collection Concerning the Welsh Barony in the Province of Pennsylvania, Settled by the Cymric Quakers in 1682|publisher=Herald Press|page=112}}