Tynewydd was the earliest Calvinistic Methodist Cause in the area, with the first chapel built in 1765 and rebuilt in 1822 to accommodate 600. The chapel building was dismantled in 1953 and a new building was constructed whilst retaining the earlier vestry.

The famous Welsh composer David Jenkins (1845-1915) was from Trecastell and is buried in the chapel graveyard. The cause is part of the Rev David Jenkins’ pastorate and Mr Philip Evans is both secretary and treasurer.