Carrigrohane Castle, Medieval castle in County Cork, Ireland

Carrigrohane Castle is a ruined castle on a rocky cliff-edge above the River Lee in the village of Carrigrohane, County Cork. It consists of two structures differing in age, height, size and architecture; the larger, older building is oblong and three-storied.

The original construction is attributed to the MacCarthy family. The castle fell into disrepair in 1641 during the Irish Confederate Wars, then was repaired and became the base of the rapparee Captain Cape and his bandits, who waylaid travellers and plundered the countryside. By the late 18th century it was again a ruin; it was restored in the mid-19th century, reputedly by Thomas Newenham Deane and Benjamin Woodward, renovated further in the 20th century and used as a family home from the late 20th century.

Local lore gives the castle a monster: Hell's-Hole, a deep pool overhung by limestone cliffs at a river bend upstream, is said to be haunted by a "monstrous biped, having a mane like a horse, and a body like an eel". The castle's Irish name is Caisleán Charraig Ruacháin.

The castle stands on a rocky cliff-edge above the River Lee in Carrigrohane village, barony of Barretts, County Cork. The rock face drops to the water, so approach the grounds from the village side and keep back from the cliff edge. The cave at the base of the rock is reached from below, not from the castle level.

Local residents believe a cave at the base of the rock connects with the Ovens caverns, about 4 miles (6.4 km) away. Upstream at a river bend, a deep pool called Hell's-Hole lies beneath overhanging limestone cliffs; folklore describes a monstrous biped there with a horse's mane and an eel's body.