Hearst Castle stands on a San Simeon hill that William Randolph Hearst called La Cuesta Encantada, the Enchanted Hill. Its modern history began in 1865, when his father, mining entrepreneur George Hearst, purchased about 40,000 acres of ranchland along California's central coast. The family used the remote property for camping and riding. After Phoebe Apperson Hearst died in 1919, her son inherited the ranch and asked architect Julia Morgan to replace the family's rough hilltop camp with something more permanent. That modest request opened one of the longest and most unusual architectural collaborations in American history.

Morgan, the first woman licensed as an architect in California, began work with Hearst in 1919. Construction continued almost constantly for twenty-eight years. The estate grew from proposed bungalows into a Mediterranean Revival complex dominated by Casa Grande and three guest houses. Hearst and Morgan repeatedly revised rooms, façades, terraces, pools, and gardens. European ceilings, choir stalls, fireplaces, sculpture, and entire architectural fragments from Hearst's art collection were incorporated into reinforced-concrete buildings engineered for an earthquake-prone landscape. The Neptune Pool was rebuilt several times, while the indoor Roman Pool became an elaborate composition of mosaic tile inspired by antiquity.

During the 1920s and 1930s Hearst used San Simeon as both a residence and a stage for his public influence. Guests arrived by private train, automobile, or the estate airfield. Political leaders, publishers, aviators, athletes, and film stars gathered for dinners, horseback rides, tennis, swimming, and screenings in the private theater. Charlie Chaplin, Cary Grant, Clark Gable, Winston Churchill, and Calvin Coolidge were among the visitors associated with the hill. Actress Marion Davies, Hearst's longtime companion, often served as hostess. The estate thus became an informal meeting place linking Hollywood, journalism, business, and national politics during the years when Hearst's newspapers reached millions of readers.

The Great Depression slowed but did not end construction. Work continued through changing designs, financial pressures, and wartime restrictions. By 1947 the estate contained 165 rooms and extensive gardens, terraces, walkways, pools, service buildings, and remnants of what had once been the world's largest private zoo. Yet it was never formally finished. Declining health forced Hearst to leave San Simeon in 1947, and he died in Los Angeles in 1951. The unfinished character of the property records the working process between an exacting patron and an architect capable of turning his shifting ideas into durable structures.

In 1957 the Hearst Corporation gave the hilltop estate, many furnishings, and a surrounding tract to the State of California. It opened to public tours the following year as Hearst San Simeon State Historical Monument. Later conservation campaigns addressed roofs, stonework, decorative tile, historic interiors, and damage from weather and earthquakes. Hearst Castle now preserves more than a spectacular house: it documents California ambition, the rise of mass media, Julia Morgan's architectural achievement, and the social world created by one of the twentieth century's most powerful publishers. The estate also served as a working ranch, and its hilltop spectacle depended on a large, largely unseen workforce of builders, craftspeople, gardeners, cooks, chauffeurs, and animal keepers. Their labor connects the celebrated entertaining rooms to the economic and social history of the wider San Simeon property.