Ballincollig is a satellite town and largest town (not including Cork City) in County Cork, Ireland, approximately 9 km west of Cork city. It is located beside the River Lee on the R608 regional road. In 2006 the population of Ballincollig DED was 16,308. The nearest towns include: Ballinora, Ovens, Killumney, Inniscarra, Blarney (home of the Blarney Stone), and Tower. It is located beyond the Green Belt from the Cork city suburbs of Bishopstown and Wilton.
The Barrett family (after whom the barony which contains Ballincollig is named) built Ballincollig Castle during the reign of Edward III. The castle was taken from Andrew Barrett by rebels in 1641, but they were expelled by English Parliamentary forces under Murrough O'Brien, Earl Inchiquinn, in 1645. It was garrisoned for James II in 1689, during the Williamite war in Ireland, then remained unoccupied after his defeat, and fell into decay.
The Ballincollig Royal Gunpowder Mills were opened in 1794 by Charles Henry Leslie, a prominent Cork businessman. Eleven years later, the mills were bought by the British, who were preparing for war with Napoleon, and the barracks were built to protect the supply of gunpowder. It was one of the largest gunpowder mills in the British Isles. In 1837, the mill employed several hundred workers, and by 1880, Ballincollig was one of the largest industrial establishments in Cork, with the mill employing many men and boys from the area.
With the closure of the Gunpowder Mills in the early 1900s, Ballincollig became little more than a small village on the road from Cork city to the larger market town of Macroom. The 3rd Royal Munster Fusiliers (Reserve) Battalion were stationed there during the Great War. Other Regiments stationed in the Barracks before it was decommissioned were 1st Field Artillery Regiment and 8th Field Artillery Regiment (FCÁ). The recently decommissioned Murphy Barracks was a major source of employment. In the 1970s, Ballincollig developed as much more of a satellite town, with many housing developments constructed around the old village, and housing people who worked in Cork city or its suburbs. This expansion continued through the late 80s and 90s. Consequently the town's population has risen dramatically, particularly with the westward expansion of the town. Ballincollig has grown to be second largest town in County Cork after Cork City.