Medmenham Abbey, Abbey House and Wall with Arch to Forecourt

This former mansion, now two houses, occupies the site of, and possibly incorporates masonry from, the Cistercian Abbey of St. Mary. The main structure was built in 1595 for Sir Francis Duffield. In 1755, Nicholas Revett added a ruined folly tower and a "cloister" arcade to the southeast for Sir Francis Dashwood and the Medmenham Club. A west wing was added, and the remainder of the building was extensively restored in 1898 by Romaine Walker for Mr. Robert Hudson of Danesfield.

The building is constructed of dressed chalk block, with the tower and north wing partially of flint. Sections of the west-facing walls and a small part of the east front are half-timbered with herringbone brick infill. Only the east porch, north wing, and the 18th-century follies retain much original masonry. The roofs are covered with plain tiles, and the chimneys feature ‘V’ pilasters and offset heads.

The building is two stories and an attic. The east front is arranged as an E-plan with an off-centre, three-story gabled porch. The windows are largely irregular, moulded mullion and transom windows, mostly of chalk, with wooden frames in the half-timbered sections. There are two gabled dormers. The porch and right gable have Tudor hoodmoulds over the windows, and circa 1900 coped gables with small ball finials. The porch doorway has moulded stops and a frieze inscribed with "Fay ce que voudras," the motto of the Medmenham Club, above a lozenge panel. A single-story, flat-roofed extension sits in front of the bays to the left of the porch, with another small extension set at a right angle.

Attached to the front of the left wing is an 18th-century folly tower, with a ruinous outline, buttresses, arches, and traceried two-light windows to the south and west sides. The arches are moulded and two-centred, built upon semi-quatrefoil piers with slender angle shafts and moulded caps; the east arch is taller than those to the north and south. A lower bay with similar arches is to the left. The south front includes an 18th-century "cloister" with four bays of moulded arches to the right, along with two dormers with cross casements and coped gables. Other fenestration was inserted in 1898 and during the 20th century, as was a gabled bay and a 1898 extension to the left. The interior was remodelled in 1899 and in the 20th century.

Historically, Medmenham Abbey and its grounds served as the setting for meetings of the Medmenham Club, later known as The Hell-Fire Club, in the late 1750s.