Ballinalacken Castle, 15th-century tower house in Killilagh, Ireland.

Ballinalacken Castle is a 15th-century tower house in County Clare that rises from a limestone outcrop where several roads meet. The structure shows clear traces of medieval military design combined with later residential additions that expanded its size and changed how it was used.

Lochlan MacCon O'Connor reportedly built a fortress here in the late 14th century. The O'Connors lost the territory in 1564, and in 1584/5 the castle was formally ceded to Sir Turlough O'Brien. After the 1641 rebellion, Turlough's son Daniel petitioned the English Commission in 1654 to spare the house from demolition; he or his son Teigue built the expansion. A Captain Hamilton gained ownership under the 1667 Act of Settlement, but the O'Briens regained possession.

The name likely comes from Baile na leachan, Irish for town of the flagstones or tombstones, or from Beal Áth na Leacha, ford-mouth of the flagstones. The O'Briens, one of Ireland's most powerful families, held the castle for centuries and built several others in the west. The residence became a guest house in 1938.

The tower sits at a road junction that connects several directions, making it straightforward to locate while exploring the area by car. The surrounding landscape offers views across fields and hills, so you can walk around the site and take in the wider setting.

The bow-fronted bungalow beside the tower was built in the 1840s as the home of Lord O'Brien, likely for John O'Brien MP, who died in 1855. Inside are a marble fireplace carved from a single slab, a circular centre-roof window, original stained glass and an O'Brien stone crest. It became a guest house in 1938.