Although the river has been the subject of arterial drainage schemes, it is generally fast flowing over a stoney bottom.

Maynooth Castle is built between the Lyreen and its tributary the Joan Slade River.

[3] The Lyreen and Rye meet to the east of Maynooth and flow on through the estate of Carton House.

The Rye then flows under the Royal Canal, which is carried in the Leixlip aqueduct almost 100 feet (30m) above.

[6] Later the Rye Vale distillery was built, producing more than 20,000 gallons of whiskey annually in 1837.