Castlekeeran is a former monastery and a National Monument in County Meath, Ireland.

[3][4] Castlekeeran was founded by Ciarán the Pious of Bealach-duin (died 14 June 770).

[6] They are called termon crosses (from the Irish tearmann, "border") which marked the sānctissimus, the holiest part of the monastery around the church.

An Ogham stone present reads COVAGNI MAQI MUCOLI LUGINI, meaning "Cuana son of the people of Luigni."

The Luigni were noted in Meath from the 8th century onward, and give their name to the barony of Lune.