Diamond Hill, 39 Braniel Road, Hillhall, Lisburn, County Antrim, BT27 5JJ

Diamond Hill is a four-bay single-storey direct-entry vernacular farmhouse built around 1800, located at the end of a long lane west of Braniel Road in Lisburn, County Antrim. The building is rectangular on plan with single-storey extensions at a lower level to each side, a projecting porch to the front (a later addition), and a single-storey extension under a catslide roof with a flat-roof porch to the rear.

The roof is pitched with natural slate and roughcast rendered chimneystacks, each topped with a single clay pot. Partial cast-iron half-round rainwater goods remain. The walls are of rubble stone and brick, roughcast rendered and painted white. Windows are mainly 2/2 timber-framed sliding sash with vertical glazing bars and horns, set in deep reveals with projecting painted masonry sills.

The principal elevation faces southeast and is irregularly arranged, with a projecting porch to the left of centre and two windows to either side (the far right window is set at a greater distance). The flat-roof porch, a modern addition, opens to the northeast with a modern timber door and a timber-casement window to the southeast. The southwest gable is abutted at a lower level by an extension with a corrugated tin roof. The southeast elevation contains two leaded casement windows. The northwest elevation contains two early timber-sheeted doors accessed by rubble stone steps, and the gable is abutted by a metal-framed conservatory. The rear elevation (northwest) has a window to the far left and is almost entirely abutted by a lean-to containing three timber casement windows, with a single window to the northeast elevation. A flat-roof porch with a modern timber door and window is accessed by three masonry steps. The northeast gable is abutted by an extension at a slightly lower level, now used as a garage, and features a metal shutter and canopy; its elevations are blank.

To the rear stands a double-height slated rubble stone barn with red-brick dressings, abutted at its north gable by a single-storey lean-to. The south gable has external steps leading to an early timber-sheeted door. The east elevation, facing the yard, contains two timber-sheeted stable doors flanked by two timber-framed windows with a smaller timber-sheeted opening above. The lean-to has a timber-sheeted door and metal-framed lattice window. The west elevation has a single opening to the attic at centre and is punctuated at mid-height by a series of diminutive openings.

Northeast of the house is a stable-block with a corrugated tin roof, partially restored with concrete blocks and two replacement stable doors. Its right section contains three early stable doors and two metal-framed lattice windows. To the southeast is a variety of agricultural buildings arranged around a yard, the earliest of which is a linear single-storey range with rendered walls, metal-framed windows, and early timber-sheeted doors. To the north is a large corrugated metal agricultural shed; to the west is an earlier corrugated metal shed, abutted to the south by a timber shed with a pitched felt roof opening onto the yard.

The property is located at the end of a long lane and surrounded on all sides by farmland. A small raised lawned and shrubbed garden to the front is partially enclosed by roughcast rendered walls with a cast-iron latch-gate; it is bounded to the lane by a grass verge. To the rear is a partially ruined rubble stone slated byre and corrugated metal outhouse and shed. Modern wrought-iron and metal farm gates provide access to farmland to the north, east, and west.

The house first appears on the first edition Ordnance Survey map of 1834 as an oblong structure in the townland of Hill Hall. None of the current outbuildings are depicted on this map; however, the stable block extension abutting the southwest gable and the extension now used as a garage abutting the northeast gable may have been constructed by this early period, as there is no discernible change to the length of the farmhouse on later map editions. By the second edition of the Ordnance Survey (1859), a small return or out office is first visible, though this has since been replaced by a single-storey lean-to constructed in the early twentieth century. The former byre to the north of the dwelling had also been erected by this time. The first recorded occupant was Robert Diamond, a local farmer who rented the property from the Marquis of Downshire. Griffiths Valuation of 1861 records the house and its offices valued at £2 10s. By 1901, the house had passed to George Diamond (57), who lived there with his niece Mary Jane Diamond (21). The Census Building Return indicates the dwelling originally had a thatched roof until at least 1911 and was described as a second-class dwelling with five or six inhabited rooms. The fourth edition Ordnance Survey map (1919–20) depicts the rubble stone barn west of the dwelling for the first time, though it likely dates much earlier. The 1911 census out-office return records that besides the stable block and barn, the farm possessed a cow house, piggery, fowl house, boiling house, and potato house, several of which were housed in the surviving outbuildings. The three more modern farm buildings to the east, including an additional stable block and corrugated metal shed barn, were constructed between 1920 and the 1969 Ordnance Survey map edition.

Despite some alterations, including the conversion of the northeast extension to a garage and the partial ruin of the former byre to the north, the farmhouse and its surviving outbuildings remain in relatively good condition and continue to be occupied.