Coordinates: 51°37′19″N 2°49′07″W / 51.621896°N 2.818660°W / 51.621896; -2.818660
Llanvaches or Llanfaches is a village and community parish within the boundaries of the city of Newport, Wales. It lies to the east of the urban area, in the historic county of Monmouthshire and the preserved county of Gwent.
Llanvaches is located roughly midway between the market town of Chepstow and the city of Newport. The village lies just north of the A48 road and below Wentwood, with both Newport centre and Chepstow about 7 miles (11 km) distant.
The village is named after Saint Maches (Latin: Machuta), a daughter of Saint Gwynllyw or Woolos and sister of Saint Cadoc, who according to tradition lived a humble life as a shepherdess in the 5th century but was killed by robbers stealing her finest ram. Saint Tathan, Abbot of nearby Caerwent, to whom the murderers confessed their crime, built a church on the spot where she was killed, which became known as Merthyr Maches and later Llanfaches (the letter m mutating to -f- in Welsh).