St Laserian's Cathedral sits in the small settlement of Old Leighlin, two kilometres west of the village of Leighlinbridge itself — a reminder that the two places are connected but distinct. The cathedral is one of the smallest in Ireland: a low cruciform building with a fifteenth-century west tower, much of the rest dating from a thorough Victorian restoration, and a few much older fragments built into the fabric.
Inside, look for the medieval font, the Maguire tomb, and the chancel arch. The churchyard contains a holy well associated with the founder, St Laserian, and a small stone-walled cell where the saint is said to have prayed. The cathedral is part of the Church of Ireland Diocese of Cashel and Ossory and is usually open in daylight hours.