Chwilog (Welsh pronunciation: [ˈχwiːlɔɡ]) is a village in Gwynedd, north Wales, and located on the Llŷn Peninsula.

[4] In the 2021 census of the UK, the Llanustumdwy community with a 60km sq radius, which includes Chwilog had a population of 1917 inhabitants.

It is a wide tree-lined avenue created in the 18th century for transporting lime, coal, and peat from the coast to the upland farms of Eifionydd, including Plas Hen locally.

A son of Llwyd married a descendant of Hywel Coetmor, he had sided with Prince Owain Glyndŵr during the early 1400's Welsh rebellion.

[10][11] Near Chwilog is Talhenbont Hall, a manor house (plas) built in 1607, it is now a Grade II listed building.

The property, formerly named Plas Hen, was inherited in 1870 by the future Baronet Hugh Ellis-Nanney of Gwynfryn and Cefndeuddwr.