Knocklong — Cnoc Loinge, "Hill of the Camp" — became the ancestral seat of the O'Hurley family, one of the great Gaelic dynasties of Munster. The strategic hilltop commanded the fertile Golden Vale, controlling passage through south County Limerick.

The O'Hurley Tower — an almost entirely square stone castle — was constructed on the hilltop. It served as the O'Hurley stronghold for generations. Two walls still stand today, described historically as "on an eminence commanding very extensive views." An ancient church stood nearby.

Following the Flight of the Earls, the O'Hurley lands faced plantation under the Munster scheme. The nearby Ryves Castle also dates from this era. Much of the land around Knocklong passed to English proprietors, fundamentally changing the social fabric of the parish.

Like much of rural Limerick, Knocklong suffered deeply during An Gorta Mór. The parish saw significant population decline through death and emigration. Many families departed for America and Australia — some carrying stones from O'Hurley Tower as mementos of home.

On 13 May 1919, one of the most dramatic events of the Irish War of Independence took place at Knocklong railway station. IRA volunteers — including Séumas Robinson, Seán Treacy, Dan Breen and Seán Hogan — rescued Hogan from a train guarded by RIC constables. Two RIC men were killed and several IRA men wounded. Knocklong was put firmly on the map of Irish revolutionary history.

Garryspillane GAA Club was founded in 1952 in the parish of Knocklong/Glenbrohane. Adopting black and amber colours and the nickname "The Bouncers," the club is almost exclusively a hurling club, with football played through an amalgamation with neighbouring Galbally. Their grounds are at Knocklong Sports Field.

Dan Dooley opened his first garage in Knocklong in July 1961, beginning a business dynasty that would become one of Limerick's most recognised names in the motor trade. Now an authorised Ford dealership, the Dooley name has served generations of families across Limerick and Tipperary.

Knocklong sits 35km south of Limerick City between the Galtee and Ballyhoura Mountains. Garryspillane GAA are reigning Premier Intermediate Hurling Champions (2025). Local businesses thrive. And the community's deep sense of history and identity is as strong as ever.