The building is dated 1760 and initialled PEE. The initials are said to refer to Philip Endale who opened the inn in the eighteenth century. The building, however, appears to be probably late C17 in origin so the date may refer to when it was refurbished as a public house. It remained The Manson Inn until c1965.

The interior has been altered in the late twentieth centruy since it was returned from public house to domestic use. The attic shows principal rafter trusses, halved and pegged at the apex and with through purlins.

The building is wholly rendered and painted, probably over rubble stone, with a Welsh slate roof. Single depth central entry plan with an additional bay on the right and a continuous outshut on the rear elevation. It hast two storeys and an attic, and three windows. It has two part-glazed doors, windows are 3 over 3 pane sashes. All these features are late from the late twentieth century. A plaque under the eaves is inscribed 1760 PEE. It has a fairly steeply pitched roof with gabled dormer with 2 + 2 pane casements, a stack on junction with the adjoining house and on the ridge to right.
Rear elevation has long catslide roof coming low over the single storey outshut. Its modern features are two rooflights, and an added late twentieth century conservatory.

Hen Dafarn has been included for its special architectural interest as one of a pair of small Georgian houses on the outskirts of Monmouth.

SOURCE: CADW LISTED DATABASE RR 29/01/2007