Leixlip is a civil parish and a townland located in the north-eastern corner of County Kildare, Ireland. The civil parish is mainly in the ancient barony of Salt North with a small part in the neighbouring barony of Newcastle. It is centred on the town of Leixlip. In geology, the parish rests on a substratum of limestone, and contains chalybeate springs. It lies at the confluence of the River Liffey and the Rye Water.

Leixlip Louisa Bridge is a railway station in the north-eastern corner of County Kildare, Ireland. It is one of two stations that serve the civil parish of Leixlip, the other being Leixlip Confey. Both stations lie on the Dublin to Maynooth commuter route. It is one of the few stations in the Iarnród Éireann network in which the station building is located directly over the platforms, on a bridge.