Chateau-sur-Mer was completed in 1852 as a French villa for William Shepard Wetmore, a merchant in the China trade, who was born on January 26, 1801, in St. Albans , Vermont. The builder was Seth Bradford; the structure is a landmark of Victorian architecture, furniture, wallpapers, ceramics and stenciling. Mr. Wetmore died on June 16, 1862, at Chateau-sur-Mer, leaving the bulk of his fortune to his son, George Peabody Wetmore (later Governor of Rhode Island and a United States Senator), who married Edith Keteltas in 1869. During the 1870s, the Wetmores departed on an extended trip to Europe, leaving architect Richard Morris Hunt to remodel and redecorate the house in the Second Empire style. As a result, Chateau-sur-Mer displays most of the major design trends of the last half of the 19th century. The house is constructed of Fall River Granite.
Unlike most of the "cottages" built in Newport during this period, Chateau-sur-Mer was one of the few built as a year round residence. This was because the Wetmores were a New England family who made Newport their home.
In March 2006, Kathleen Styger and Michelle Styger, as interns for the Preservation Society of Newport County, conducted extensive research for descriptions on the interior of the Chateau-sur-Mer estate as part of the National Historic Landmark nomination submitted to the Department of Interior resulting in recognition as a National Historic Landmark.
It was declared a National Historic Landmark in 2006.
The former carriage house and stables for the Chateau-Sur-Mer estate are owned by Salve Regina University and are currently being renovated as a center for visual art and cultural and historic preservation known as Wetmore Hall.
Two HABS photos and one other older photo are available.