Llanfair-ar-y-bryn zo ur gumuniezh e kontelezh Sir Gaerfyrddin, e mervent Kembre, e-kichen Llanymddyfri. 227,6xa0km zo achane da Gerdiz E 2011 e oa poblet gant 611 a dud, ha 200 anezho (32,7%) a oa kembraegerien.<ref>{{cite web| url=http://www.ons.gov.uk/ons/rel/census/2011-census/key-statistics-for-unitary-authorities-in-wales/stb-2011-census-key-statistics-for-wales.html| title=Statistical bulletin: 2011 Census: Key Statistics for Wales, Mawrth 2011| publisher=Swyddfa Ystadegau Cenedlaethol (The Office For National Statistics| accessdate=2014-04-09}}</ref>.