Courtyard and ranges at Mona

To the rear of the main house and attached to the northwest wing is a U-shaped range of outbuildings surrounding a large courtyard. These buildings are constructed from local rubble masonry with dressed stone heads above the coachhouse bays, while other openings feature slate lintels. The roofs are covered with slates arranged in diminishing courses, and there is a single roughly-dressed stone ridge stack at the northeast end of the southeast range.

The courtyard is highlighted by a lofted five-bay coachhouse, which is centrally located along the southwest range and is taller than the adjacent buildings. The ground floor of the coachhouse has five bays with shallow elliptical ashlar heads; some bays feature double boarded doors, and the central bay has openings at both the front and back, originally leading to the courtyard beyond. Each bay includes a centrally placed first-floor opening; the central three are louvred, while the opening to the left (southeast) has a six-pane light, and the one to the right (northwest) is now boarded up.

The adjoining buildings serve as lofted stables, which include first-floor accommodation for servants. These ranges have boarded doors, and some original six-pane lights remain, although other openings have been blocked, boarded, or left open. The roof at the northeast end of the northwest range has been replaced with corrugated iron.