9 Derry Road, Strabane, Co Tyrone, BT82 8DT

Abercorn Factory is a three-storey, nineteen-bay brick shirt factory on Derry Road, Strabane, built around 1880 on the site of an earlier factory that dated from approximately 1865. It is rectangular on plan, facing west, and was constructed for the firm of Stewart & McDonald, two Scotsmen who, according to the Strabane Chronicle of 19 December 1987, brought their own builders and bricks from Scotland, shipping the materials by sea directly to Derry and then transporting them by horse-drawn canal barges to the canal basin at Strabane, from where the bricks were wheeled by iron barrows to the building site. The repetitive, cliff-like façade would have been a striking and unusual presence in the 1880s and remains a well-known landmark on the Derry Road, as well as a tangible link to Strabane's industrial heritage.

The exterior walls are painted red and yellow brick laid in English garden wall bond. The roof is pitched and covered in fibre cement artificial slates with plastic rainwater goods fixed to a timber fascia. Window openings are camber-headed with brick arches and stone sills, and all now contain replacement timber casement windows. The three-storey west front elevation is nineteen windows wide and carries painted lettering between the floors reading "PORTER & COMPANY, ABERCORN FACTORY". Security steel grilles protect the ground and first floor windows. There are two door openings fitted with replacement timber frames, glazed hardwood doors, sidelights and overlights, each protected by steel roller shutters, and all opening onto a concrete universal access ramp. The northernmost bay has a segmental-arched door opening formed in brick, reinforced with a steel plate, and fitted with a steel roller shutter. The southernmost bay has a segmental-headed carriage arch formed in brick with rounded brick to the piers and a rendered keystone to the arch, also reinforced with a steel plate, giving vehicular access to the rear. To the left of the carriage arch is a square-headed opening formed in brick providing pedestrian access to the rear along a concrete footpath.

The north side gable is four windows wide with painted red brick walls and windows to the first and second floors only. This elevation fronts onto the front yard of the adjacent Masonic Hall. The rear elevation is largely obscured at ground and first floor level by a modern sheeted steel factory extension built around 1970, except above the carriage arch at the south end, where four windows are visible on all three floors. The upper floors of the rear elevation retain their original unpainted brick walling with yellow brick surrounds to the window openings. The ground floor of the rear elevation is pebbledash rendered, with rendered keystones left exposed to the carriage arch and pedestrian arch openings. The south side gable has been rebuilt above ground floor level in modern brown brick and is four windows wide, fronting onto the gardens of neighbouring houses.

The integral carriage arch in the southernmost bay gives access to an attached factory building to the rear built around 1970, and to a former manager's house to the east.

The factory's history is well documented. The site first appears in valuation fieldbooks dated 1864, described as a "Shirt factory, ware rooms, offices and yard" valued at £90 and leased by William Gourlie & Son from the Duke of Abercorn, which also gave the site its name, the Abercorn Shirt Factory. The fieldbook records a steam engine of 8 horsepower and notes the dimensions of the building. Sixteen workers' houses behind the factory were also recorded at this time, along with a smaller terrace of four houses to the east, all leased from the factory occupier. By 1875 the factory had been briefly taken over by Mason Kennedy, and in 1878 by Messrs J and R Pritchard & Co. In 1882 Stewart & McDonald took over and rebuilt the factory in its present form. At the height of the shirt boom in the 1890s, more than 250 people were employed, many of them part-time and home workers who walked as far as ten miles from Donemana, Glenmornan and Castlefin. The factory value was reduced to £70 in 1891. In 1901 it was taken over by Miriam Stewart and Robert Keady, and in 1911 by Gallagher & Egan, at which point the value rose to £85. By 1933 the factory was listed as "at rest," and in 1935 the lessee, Margaret Gallagher, complained that she had been unable to sell it, noting that "every such factory in Strabane has either closed up or built abroad in Donegal," and that she had moved her own business to Lifford in County Donegal. During 1941 the building was occupied by HM Forces under the Defence Acts and used as stores. It was subsequently taken over by S and L Porter Ltd, held in fee, and the value rose from £50 to £120. A valuer's note from 1943 records that Porter & Co purchased the building for £2,300 and employed 120 workers operating 90 sewing machines, powered by two 3-horsepower, one 7½-horsepower, and one 5-horsepower electric motor, producing shirts exclusively from raw material to finished article. Porter and Co had originally been founded in Derry in 1907. By 1987, according to Michael G. Kennedy's history of Strabane, the Abercorn Factory employed 130 people making pyjamas, nightshirts and boxer shorts, and in that year a 10,000 square foot extension was added.

The sixteen workers' houses behind the factory, known as Factory Row and renumbered 1–16 in 1892, were described in 1935 as "old kitchen type houses in poorish repair" with a WC in the yard, a water tap but no sink, and gas lighting. By 1952 they were condemned and by 1953 five had been demolished. The smaller terrace, known as Gourleville Terrace and numbered 1–4, underwent various changes of occupation and was eventually consolidated into two dwellings by 1935, still occupied by the Gallagher family. Some of this associated housing survives to the present day.

The factory first appears on the third edition Ordnance Survey map of 1905. While most original internal and external features have been lost, the overall composition of the façade remains intact.