Subsequently, the Norman Lord Hugh de Lacy built his Motte alongside the remains of Guaire's Fort.

In 1210, King John came to Rathwire to subdue the De Lacys when he fought and won the Battle of Killucan.

While here, he also received the Gaelic King of Connacht, Cathal Crobderg O'Connor, who travelled to make his submission.

[citation needed] The origins of the name Killucan are uncertain but it probably comes from the Irish Cill Lucaine (Church of Lucan).

[citation needed] A private helicopter crash in the area, in July 2024, resulted in the deaths of two men.

[5] Economic prosperity has historically been linked with transport connections to places like Dublin,[citation needed] and the Royal Canal and the Sligo-Dublin railway line previously served the area.

[6] Sports facilities serving the area include a free golf course and fishing lake, a library and other amenities.

The twin villages reached the height of their prosperity during the 18th and 19th centuries due to the arrival of first the Royal Canal in 1805 and later the Midland Great Western Railway.

Nowadays, following effort from the Royal Canal Amenity Group, it has been restored for leisure boats from Dublin to Abbeyshrule in County Longford.

The Harbour at Thomastown (1 kilometre South of Killucan) was expanded to cater for the growing number of tourists who rent barges from there.

[7] Denis Leonard, of the Killucan Kinnegad Transport Lobby Group, stated in 2019 that "a feasibility study has to be conducted, funding secured for work on the station and planning permission sought".

[8] Bus Éireann route 115A provides a commuter service from Killucan to Dublin via Ballivor, Summerhill, Kilcock and Maynooth and vice versa Mondays to Fridays inclusive.