Ballincollig Royal Gunpowder Mills was one of three Royal gunpowder mills that manufactured gunpowder for the British Government. Located in Ballincollig near Cork city in Ireland, the powder mills were originally opened in 1794 as a private enterprise, before being taken over by the British Government during the Napoleonic Wars.

​

The mills returned for a time to private ownership in the mid-19th century, before closing permanently in 1903. In the late 20th century Cork County Council bought the mill grounds, developed a public park and opened a visitor centre. Though the visitor centre closed in 2002, many of the mill buildings remain accessible in the public park.

​

Though ruined, many of the remaining structures of the mill site are afforded National Monument status.

​

The Royal Gunpowder Mills were first established in Ballincollig in 1794, by Corkman, Charles Henry Leslie. He chose Ballincollig as a site for the gunpowder factory because of its proximity to Cork city, and because of the flat valley and its water-power potential. Leslie built a weir to produce a head of water and a canal, one and a half miles long which was fed by the River Lee and which powered his two mills at the eastern end of the site.

​

The Gunpowder Mills were of strategic importance being so near to Cork Harbour, and they attracted the attention of the British after the 1798 Rebellion. In 1804, Leslie sold the mills on a lease of 999 years to the British Board of Ordnance. To meet the demands of the British Army, during the Napoleonic Wars, the mill site was expanded tenfold and twelve new mills were added to the complex as well as new processing buildings and homes for the workers and senior officials. To improve security, a barracks was constructed in 1810,[3] and military escorts were arranged to accompany the wagons of powder to Cork Harbour. The site covered 435 acres (1.76 km2),[5] and was enclosed by a high limestone wall.

​

After the Napoleonic Wars, the demand for gunpowder fell dramatically and the mills were closed in 1815.The site was left to the elements for nearly twenty years until Thomas Tobin and his partner Charles Horsefall from Liverpool bought the mills in 1834 and transformed them into one of the most up to date industries in the country.

​

Ballincollig continued to grow into the middle of the nineteenth century, even while famine raged in other parts of the island. At this time about 500 men and boys were employed and a range of skills were in use in the mills: coopering, mill-wrighting, carpentry as well as other specialist gunpowder making skills. The population of Ballincollig, in 1886, from the Postal Directory of Munster, was 1,130 (including the military).

​

The powder at this time was largely blasting powder to meet the demands of the construction of new railways, mining and quarrying.

​

In the latter part of the century, the mills went into decline again as the demand for black gunpowder decreased as new types of explosives such as nitroglycerine were developed.

​

The mills finally closed in 1903, after the end of the Boer War, with a devastating effect on the local community. Eventually, the site came to be owned by Imperial Chemical Industries.