The Hillforest Mansion, also known as the Thomas Gaff House, is located at 213 Fifth Street, in Aurora, Indiana. Built in 1855 on a bluff above the Ohio River, it is one of the finest surviving examples of an Italian Renaissance estate house, and a rare well-preserved example of the work of architect Isaiah Rogers. The mansion, which was designated a National Historic Landmark in 1992, is owned and operated by Hillforest Historical Foundation. It is located in the Downtown Aurora Historic District.