This great threadworks was once the largest industrial undertaking on the Upper Bann. The buildings all date from the second half of the 19th Century. The original partnership to build a spinning mill was formed by Hugh Dunbar of Huntly and W A Stewart of Edenderry in 1834. Stewart died in 1837 and Robert Thomson took his place to form "Dunbar, Thomson & Co". Thomson was soon bought out by Dunbar and replaced by J W McMaster of Armagh. In 1839 James Dickson, elder son of Andrew Dickson of Glenconway, Co Antrim, was also taken into the partnership. The business was divided into two distinct firms in 1843, "Dunbar, McMaster & Co" for thread spinning and "Dunbar, Dickson & Co" for manufacturing and bleaching.

The Ordnance Survey found the five storey spinning mill in course of erection. The iron breast wheel of 20ft in diameter and 22ft in width with an estimated 90hp was already installed. The spinning mill and workers’ houses were valued at £123 16s. Gilford mill employed 215 workers in 1838. Stuart, the factory inspector, described the mill in 1846 as ‘the largest or certainly one of the largest, of the flax-spinning factories in Ireland.’ Hugh Dunbar died in 1847, leaving no sons to succeed him, and the business eventually passed to the McMaster family after prolonged difficulties between them and the Dicksons.

In 1886 a private company was formed consisting of Hugh Dunbar McMaster and his six brothers. "Dunbar McMaster & Co" joined the "Linen Thread Co Ltd" in 1901. The mill ceased production in the 1980s and is awaiting redevelopment.