Standard Welsh Place-names
Notes
This is the form recommended in the national standard reference work, A Gazetteer of Welsh Place-Names (University of Wales Press, 1967). One should not deviate from its recommendations without good reason here.
The word llannerch has a double -n-, conforming to the principles of standard Welsh orthography. Note, however, that the National Trust site is called Llanerchaeron (written with a single -n-).