Sure everyone knows how to get there, you start at Llanrhaeadr-ym-Mochnant, go past Pontrhydfendigaid, through Rhosllannerchrugog, then follow the path to Llanfair Mathafarn Eithaf and then it's just up the road :S
It's the longest place name in Europe. Known as Llanfair to most people. It translates to "St Mary's Church in the Hollow of the White Hazel near a Rapid Whirlpool and the Church of St. Tysilio near the Red Cave".