Rattin Castle is a substantial late 15th or early 16th-century defensive tower in County Westmeath near Kinnegad, built to protect Anglo-Norman lands originally owned by Hugh de Lacy and granted to the D'Arcy family. Standing approximately 30 metres tall with entrances in its eastern wall, the castle was surrounded by a significant bawn wall that has since been removed. The fortress remained strategically important until the Irish Rebellion of 1641, when it was forfeited, and today its impressive ruins stand largely intact near the M6 motorway, a testament to its significance in the Anglo-Norman defensive system.