Bwlch-derwinBwlch-derwin is a village in the community of Dolbenmaen, in the county of Gwynedd, Wales. Historically in Caernarfonshire, the village is situated within Snowdonia.HistoryBwlch-derwin is known as a recognised battlefield site for the Battle of Bryn Derwin, where Llywelyn ap Gruffudd battled his two brothers for complete control of the Kingdom of Gwynedd in June 1255. It is a known site of archaeological interest. The local forests have reportedly been used as an illegal dump site.GovernanceBwlch-derwin is part of the local authority of Gwynedd Council.