Trellech United is a community and electoral ward in the county of Monmouthshire, Wales.

The community is located directly south of the town of Monmouth and is bordered to the east by the River Wye, the other side of which is the English county of Gloucestershire.

The mines at Trellech provided the metals for the weapons and armoury of the De Clare family, headed by the Earl of Pembroke in the 13th century.

[3] St Anne's Well, to the east of Trellech, is an ancient water source believed to have healing powers.

[3] There are sixty-seven listed buildings and structures in the community, including four churches, three Grade II* houses, a Grade II* listed dovecote and the Bigsweir Bridge over the Wye.