city, Napa county, western California, U.S. Located just northeast of Santa Rosa, Calistoga lies near the head of Napa Valley, 80 miles (130 km) north of San Francisco. Located in an area of natural hot-water geysers (geyser) and mineral and mud springs, it was founded in 1859 as a health spa by Sam Brannan. The city supposedly received its name through a promotional twist of its founder's tongue (he reportedly said “Calistoga of Sarafornia” instead of “Saratoga of California”).

The city's “Old Faithful Geyser of California,” which shoots hot water 60 feet (20 metres) into the air, erupts regularly every 30 minutes. In the summer of 1880, author Robert Louis Stevenson (Stevenson, Robert Louis) and his wife, Fanny Vandegrift Osbourne, honeymooned near an abandoned silver mine in the vicinity of Mount St. Helena, which lies 8 miles (13 km) northeast; there he prepared notes for The Silverado Squatters (1883). His sojourn is commemorated by a monument within what is now Robert Louis Stevenson State Park. A petrified forest containing giant redwood fossils and Bothe–Napa Valley State Park are nearby. Calistoga has flourished as a popular resort and has developed an important wine industry, comprising several vineyards. The sale of Calistoga Brand waters (sparkling mineral and mountain spring) is also economically important. The area's history is preserved at the Sharpsteen Museum. Inc. town, 1886; city, 1937. Pop. (1990) 4,468; (2000) 5,190.