According to the United States Census Bureau, the city has a total area of 2.6 square miles (6.7 km²), all of it land.
Average annual rainfall is with measurable precipitation falling on an average of 66 days each year. The wettest year was 1983 with and the dryest year was 1976 with . The most rainfall in one month was in February 1986. The most rainfall in 24 hours was on February 17, 1986. Snow often falls in the nearby mountains during the winter months, but is rare in Calistoga. On January 3, 1974, 3.0 inches of snow fell in the city.
The Upper Napa Valley was once the home of a significant population of Indigenous People, called the Wappo during the Spanish colonial era of the late 1700’s. With abundant oak trees providing acorns as a food staple and the natural hot springs as a healing ground Calistoga was the site of several villages. Following Mexican Independence, mission properties were secularized and disposed of by the Mexican government with much of the Napa Valley being partitioned into large ranchos in the 1830s and 1840s. The first American settlers began arriving in the 1840’s, with several taking up lands in the Calistoga area.
Samuel Brannan was the leader of a settlement expedition on the ship Brooklyn landing in Yerba Buena (San Francisco) in 1846. He published San Francisco's first English language newspaper, the California Star. Following the discovery of gold in Sacramento, Brannan pursued many business ventures, which made him California’s first millionaire and became a leader in San Francisco's Committee of Vigilance (the much feared Vigilantes). Fascinated by Calistoga’s natural hot springs, Brannan purchased more than with the intent to develop a spa reminiscent of Saratoga in New York. His Hot Springs Resort surrounding Mt Lincoln with the Spa/Hotel located at what is now Indian Springs Resort, opened to California's rich and famous in 1862. In 1868 Brannan's Napa Valley Railroad Company's track was completed to Calistoga. This provided an easier travel option for ferry passengers making the journey from San Francisco. With the addition of railroad service, Calistoga became not only a destination, but also the transportation hub for the upper valley and a gateway to Lake and Sonoma Counties. A 6 meter diorama of this early Calistoga can be seen in the Sharpsteen Museum.
Calistoga's economy was based on mining (silver and mercury) agriculture (grapes, prunes and walnuts) and tourism (the hot springs). One of the early visitors was Robert Louis Stevenson. He had yet to write his great novels, met Fanny Vandegrift in France, followed her to San Francisco and, after she had obtained a divorce, married her in May, 1880. Three days later they were on their way to honeymoon at the Calistoga Hot Springs Hotel. Desiring to stay in the area, they moved from the hotel to an abandoned cabin at the nearby Silverado Mine on Mount Saint Helena. While working on other stories Stevenson kept a journal which became the Silverado Squatters describing many local features, residents and characters.
Calistoga made national headlines in 1881 when Anson Tichenor claimed that he had invented a way to extract gold from the waters of the hot springs. Tichenor's invention was soon proved to be a fraud.
In 1920 Giuseppe Musante a soda fountain and candy store owner in Calistoga was drilling for a cold water well at the Railway Exchange when he tapped into a hot water source. In 1924 he set up a bottling line and began selling Calistoga Sparkling Mineral Water. The company became a major player in the bottled water business after Elwood Springer bought the small bottling plant in 1970 known today as Calistoga Water Company.
Today, Calistoga retains its charm of yesteryear with a walkable downtown much as it was when spa visitors arrived by train.
At the very top of the Napa Valley, centrally located between Napa and Sonoma counties, Calistoga remains the historic hot springs resort destination of wine, water, and wellness.
Named a Distinctive Destination by the National Trust for Historic Preservation in 2001, Calistoga enables a visitor to see wine country as it was before freeways and fast food - only two-lane roads lead there and fast food franchises are banned by law.
Scenes from an upcoming Disney movie "Bedtime Stories" starring Adam Sandler were filmed in Calistoga in June, 2008. Local folklore holds that the town supposedly got its name from a Spoonerism uttered by Sam Brannan. He is alleged to have said (perhaps after sampling the local vintages) that the location would become the 'Calistoga of Sarifornia'. He had meant to say the 'Saratoga of California', comparing it to the famous hot springs of that New York town.
There were 2,042 households out of which 29.0% had children under the age of 18 living with them, 47.2% were married couples living together, 8.2% had a female householder with no husband present, and 39.1% were non-families. 31.4% of all households were made up of individuals and 17.1% had someone living alone who was 65 years of age or older. The average household size was 2.51 and the average family size was 3.20.
In the city the population was spread out with 23.3% under the age of 18, 8.5% from 18 to 24, 27.0% from 25 to 44, 21.7% from 45 to 64, and 19.6% who were 65 years of age or older. The median age was 38 years. For every 100 females there were 99.6 males. For every 100 females age 18 and over, there were 94.6 males.
The median income for a household in the city was $38,454, and the median income for a family was $44,375. Males had a median income of $32,344 versus $29,844 for females. The per capita income for the city was $21,134. About 5.2% of families and 8.0% of the population were below the poverty line, including 9.5% of those under age 18 and 5.7% of those age 65 or over.
Calistoga is at the north end of the Napa Valley AVA, part of California's Wine Country. Thus there are numerous wineries within a short drive. Calistoga itself, however, is noted for its hot springs spas, a local specialty being immersion in hot volcanic ash known as a mud bath. Nearby attractions are include a geothermal geyser known as the Old Faithful of California.