Holyhead (/ˈhɒlɪhɛd/ HOL-i-hed; Welsh: Caergybi [kɑːɨrˈɡəbi], "Cybi's fort") is the largest town in the county of Isle of Anglesey in Wales. It is also a community and a major Irish Sea port, serving Ireland.Despite being the largest town in the county, with a population of 11,431 at the 2011 census, it is neither the county town nor actually on the island of Anglesey. Holyhead is located on Holy Island, which has a population of 13,659 at the 2011 census.