An archaeological watching brief was carried out at Monkyn Pyn, Thornwell Road, Wilmington, BN26 6RL in order to monitor the groundworks associated with the construction of a new extension to the rear of a mid-late 18th century house. No features, deposits or finds pre-dated the construction of the house, revealing that the Site had witnessed low-level activity up to this point in time. The remains of a demolished outbuilding, possible footpaths, and a well were found, along with refuse debris from occupation of the house. A bay had been built on to the north end of the house in the late 19th century, and this extension was observed in the varying construction of its foundations.