Coordinates: 51°35′49″N 2°52′52″W / 51.597°N 2.881°W
Llanmartin (Welsh: Llanfarthyn) is a village and parish in the city of Newport, Wales.
The parish contains several communities and is centred on the parish church, which is dedicated to St. Martin, and which gives the name "Llan" for church or holy ground. The name is an anglicised version of the Welsh Llanfarthyn which has the same meaning.
Within the parish is Underwood which has an early 1960s council housing estate that consists of houses, shops, a leisure centre, Baptist church and social club. A Westbury homes development was built in Underwood in the 1990s.
The Underwood Estate was originally developed from the former World War II Prisoner-of-war camp after the war, in the late 1940s. A few examples of the surviving former PoW huts were visible until the early 1990s, when they were demolished. The original huts stood as early community buildings. In the early 1980s several huts and a water tower were also visible on the now Waltwood Park Drive area, this area belonged to the General Post Office and was used to house old telecommunications equipment until it was sold and demolished by British Telecom who took over the site when the organisation was privatised in the early 1980s. The land was subsequently sold to Westbury homes who built the Waltwood Park Drive Development of around 220 houses on the land.