A boxy, column-fronted, 36-room mansion, Dundurn Castle once belonged to Sir Allan Napier McNab, Canadian prime minister from 1854 to 1856. It sits on a cliff overlooking the harbor amid lovely chestnut- studded grounds, and is furnished in mid-19th-century style.

Also on-site is the Hamilton Military Museum, with weapons and uniforms from the War of 1812 to WWI. Admission is free with Dundurn Castle admission.