Cefn Ila was a nineteenth-century house on a more ancient house but was destroyed by fire in 1973. It lay within parkland (nprn 700378) but is primarily noted for its well-preserved Victorian garden.
The garden survives it its entirety, with most of its structure intact, despite the loss of the house. It comprises a formal terrace garden, an informal woodland garden, an orchard including some old apple and pear trees, and a well-preserved walled kitchen garden. An important aspect is the Victorian plantings of ornamental trees and shrubs, now fine mature specimens, including some rarities. The layout and much of the plantings are attributed to Edward Lister, owner in the 1860s. 

The gardens fall into two sections: the terraces immediately adjacent to the house site and the informal wooded grounds beyond.
The terraced garden lies to the south and west of the house site. It is no longer lawned, as shown in early twentieth-century photographs. The terraces are linked by two flights of steps. They, and a path below the lower flight, are flanked by overgrown yews, suggesting former yew hedges.

The woodland garden occupies a large area to the west and south of the house. The drive curves through it, passing banks of rhododendrons. The woodland is dominated by large conifers, including fine specimens of Sugi (Cryptomeria japonica Elegans), Lawson’s cypress (Chamaecyparis lawsoniana), Scot’s pine (Pinus sylvestris), Maidenhair tree (Ginkgo biloba), Monkey puzzle (Araucaria arucana), Incense cedar (Libocedrus decurrens), Himalayan cedar (Cedrus 4 deodara) and Atlas cedar (Cedrus atlantica Glauca). Other specimen trees in the woodland include Red horse chestnut (Aesculus Carnea), Evergreen oak (Quercus ilex), lime (Tilia x europea) and yew. At the end of the drive, near the house site, is a huge Himalayan cedar (Cedrus deodara), shown clearly on the lawn in twentieth century photos.

North of the garden is an old orchard, an area of well-spaced, large old apple trees on the slope and large pear trees at its foot. Near the top of the slope a wide, levelled path runs northwards across the slope to a doorway in the south wall of the kitchen garden. The doorway has a cut stone surround and a wooden door, which appears original.

The kitchen garden is square, enclosed by roughly coursed, mortared stone walls, with flagstone coping. Along the outside of the east wall are two ruined stone bothies.

Sources:
Cadw 2013: Register of Parks and Gardens of Special Historic Interest in Wales (ref: PGW(Gt)63(MON))
Ordnance Survey, 25-inch sheet Monmouthshire XXIV.2 (1882).
Ordnance Survey, 6-inch sheet Monmouthshire XXIV (1887).

RCAHMW, 19 July 2022