Inside the tower at the western end of Leixlip church sits a font that is, in at least one respect, genuinely puzzling. It is a large rectangular block, roughly 68 centimetres long and 66 centimetres wide, rising to about 36 centimetres in height, with a circular basin carved into its upper surface. That basin measures nearly half a metre across and descends some 22 centimetres. A font is the vessel used in Christian baptism, and drain holes are a standard feature, allowing water to be disposed of reverently rather than simply tipped away. This one has none. Whether that reflects an original design choice, a later alteration, or simple wear is not recorded.

What is recorded is the font's current appearance: it has been coated in black gloss paint, a treatment that sits oddly on a piece of ecclesiastical stonework of this age and size. Paint of this kind obscures surface detail, making it difficult to assess the carving beneath or to date the object with any confidence. The font was noted in this condition by Bradley and colleagues in their 1986 survey, and it remains housed in the ground floor of the church tower, somewhat removed from the main body of the building.