Holy Assumption Monastery, a women's monastery of the Western Diocese of the Orthodox Church in America, is located in the city of Calistoga, California.

In the early 1940s, a group of nuns fleeing persecution in Soviet Russia and China arrived in San Francisco. Later, they acquired a two-story building in Calistoga on the banks of the Napa River to create a monastic dormitory. This is one of the oldest Orthodox monasteries in the USA. In 1959, a separate wooden church was built, modeled after the church in Fort Ross, which the nuns decorated with icons they created themselves.

In the early 1980s, the monastery effectively ceased to exist and became a parish church, as all the nuns left for various reasons. The residents, led by Abbess Barbara (Johnson), moved to the former St. Eugene's Desert in California and founded the Holy Cross Monastery in 1984. The monastery buildings fell into disrepair, but in 1998, thanks to the efforts of the spiritual father, Archimandrite Sergius (Gerken), restoration began, lasting ten years.

On October 8, 2009, county authorities demanded that the women's monastery of St. Barbara in Santa Paula remove the trailers where most of the community lived. Following this, on October 22, ten nuns led by Abbess Melania (Salem) moved to Calistoga, reviving the monastery.

Currently, the nuns work at an elementary school in Calistoga, engage in icon painting, and make coffins. Since 2011, the monastery, together with the parish of St. Simeon of Verkhoturye Church in Calistoga, which belongs to the Russian Orthodox Church Outside Russia, has been producing wines under the brand Calistoga Orthodox Wines.