Caergeiliog is a village in Anglesey, Wales.
It is situated within the LL65 postcode district, which is within the Holyhead post town.
LL65 is the only postcode district within the Holyhead post town.
The Holyhead post town is within the Llandudno postcode area.
Administrative Ward: Llanfair-yn-Neubwll
Administrative District: Isle of Anglesey
Country: Wales
UK Parliament: Ynys Môn