Milntown Castle was an early 16th-century castle which was situated near Milton, in Easter Ross, in the Scottish Highlands. It was built by the Munro of Milntown family, a cadet branch of the Clan Munro. In 1656, the castle and estate was sold to George Mackenzie, 1st Earl of Cromartie also known as George MacKenzie of Tarbet. He renamed the estate New Tarbat after Tarbat Castle (now more commonly known as Ballone Castle), the family's original seat near Portmahomack. Mackenzie had the Milntown Castle pulled down and only part of the basement survives. He then replaced the castle with a new mansion built nearby. When the new mansion was built, the old Milntown Castle was remodelled as part of the garden.