Newport Mansions | The Preservation Society of Newport County The Newport Mansions offers a unique trip through 250 years of American history, architecture, art and landscape design. The Preservation Society of Newport County preserves and protects the best of the area’s architectural, decorative arts, landscape and social history. Its 11 historic properties—including 7 National Historic Landmarks—trace American development from the colonial era through the Gilded Age. The Preservation Society is a non-profit organization accredited by the American Alliance of Museums.