Hill–Stead was created on as a country estate for wealthy industrialist Alfred Atmore Pope, to the designs of his daughter Theodate Pope Riddle. Egerton Swartwout of the renowned architectural firm McKim, Mead, and White translated her design into a working site plan, and construction took place over the period of 1898 to 1901. Theodate inherited the house after her parents deaths, and prior to her own passing in 1946 willed Hill–Stead Museum as a memorial to her parents and "for the benefit and enjoyment of the public". She directed that both the house and its contents remain intact, not to be moved, lent, or sold. Hill–Stead comprises, the balance having been sold off during the first years of the museum's operation. Buildings which remain part of the property include the Pope-Riddle House itself ; an 18th-century farm house; a carriage garage with an Arts and Crafts theater; a barn and additional farm buildings. Today, 19 rooms of the house are open to visitors. Remaining as it was at the time of Theodate's death, the house is extensively furnished with paintings, prints, objets d'art, and fine furniture and rugs. Highlights of the collection include major paintings by Eugène Carrière, Mary Cassatt, Edgar Degas, Édouard Manet, Claude Monet and James McNeill Whistler; prints including three engravings by Albrecht Dürer, 17 copper plate etchings and lithographs by James McNeill Whistler, and Japanese woodblock prints by artists Katsushika Hokusai, Utagawa Hiroshige and Kitagawa Utamaro; eight bronze sculptures by Antoine-Louis Barye; about 13,000 letters and postcards including correspondence from Mary Cassatt, Henry James and James McNeill Whistler; and about 2,500 photographs, including six of Gertrude Käsebier's art photographs. Hill–Stead's grounds were originally designed in consultation with landscape architect Warren H. Manning and feature a broad lawn with ha-ha and slate walkway; artificial pond; and formal, octagonal flower garden. Around 1920, landscape gardenerBeatrix Farrand redesigned the estate's Sunken Garden at Theodate's request. Due to the wartime labor shortage experienced during the 1940s, the garden grassed over leaving only the summerhouse in place. Though it was replanted in time, it was not until the 1980s that the Sunken Garden was restored to exhibit Farrand's original plan.
Hill–Stead was declared a National Historic Landmark in 1991. The Hill-Stead has also been the venue of one of the longest running poetry festivals in the country, the Sunken Garden Festival.
