Castlemagner (Irish: Caisleán an Mhaignéaraigh)[2] is a village, townland and civil parish in the Duhallow area of north-west County Cork, Ireland.

The area takes its name from the eponymous Castle Magner, a Norman-era tower house which is located approximately 500 metres (1,600 ft) east of the village itself on the eastern boundary of Castlemagner townland.

Owned by a Richard Magner during the Irish Rebellion of 1641, the tower house was largely destroyed in the late 16th century.

[5] The castle is largely in ruin, though the stair turret and parts of the surrounding bawn wall remain.

[8][9][10] Castlemagner's Roman Catholic church, which is dedicated to Saint Mary and was built c.1880, is located within the village itself.