Knocklong was originally known as Druim Damhghaire, the Ridge of the Oxen, but takes its present title from Cnoc Luinge, the Hill of the Encampment. According to tradition. King Cormac mac Airt set up his camp on this hill when he invaded Munster during the third century. The King of Munster consulted a druid, Mug Ruith. The druid used his magical powers to help the Munster men who then defeated Cormac's forces in a legendary battle said to have taken place about 250. Four centuries later, about 650, a more significant fight took place here when Dioma, King of Thomond, defeated the Connaught men, who were endeavouring to recover County Clare from North Munster. This historic battle secured Clare for the Dalcassians so Cnoc Luinge may derive its present name from an encampment of the seventh century rather than the third century. Cnoc Luinge has also been translated as the Hill of the Ships, as the tents on the hill resembled ships under sail. Another version says that there was once a lake from Emly village in County Tipperary to the hill of Knocklong, on which small boats or ships used to sail.
Although it is a small village, Knocklong played a role in modern Irish history. It is most famous for the rescue of Sean Hogan which took place at the railway station in Knocklong during the War of Independence on 13 May 1919. Seán Treacy and Séamus Robinson were joined by five men from IRA East Limerick Brigade in order to organise Hogan's rescue. Hogan was being transported by train to Cork, and the men, led by Treacy, boarded the train in Knocklong. A close-range shoot-out followed on the train. Treacy and Breen were seriously wounded in the gun fight, two policemen died, but Hogan was rescued. He was spirited away to Knocklong village, where his handcuffs were cleaved by Séan Lynch, one of the rescuers, in the local butcher's shop. However that train station has since been removed.
Gaelic Athletic Association
Knocklong is steeped in tradition and the Gaelic Athletic Association (GAA) plays a major role in the community. The village has seen many of its residents over the years succeed in winning titles with both their club Garryspillane, "The Bouncers", and with their colleges and county team Limerick. Some have even gone on to extend the tradition of hurling across the waters in London, England. One of the proudest moments of Garryspillane GAA history came in 2005 when the club won their first ever Senior Hurling Title. The same team also went on to win the All-Ireland Kilmacud Crokes mini-7s tournament.
- Michael J. Carroll. "The Castle of County Limerick". Hurleyfamilytree.com. Retrieved 24 October 2010.
- Brendan A. Creaner. "The Rescue at Knocklong". Knocklong-Rescue.com. Retrieved 8 December 2006.