The Sathorn Mansion (Luang Chitchamnongwanit Mansion) is a complex of historic buildings in Bangkok.
It was built in 1888, during the reign of King Chulalongkorn (Rama V), for Luang Chitchamnongwanit, son-in-law of Luang Sathorn Rajayukta (Yom Pisolyabutra), the wealthy Chinese businessman and government official who owned and developed the land around Khlong Sathorn. In 1910, Luang Chitchamnongwanit went bankrupt, and ownership of the mansion fell to the Privy Purse (later to become the Crown Property Bureau) in 1916.
King Vajiravudh (Rama VI) bestowed the mansion to Chao Phraya Ram Rakhop, and later, in the 1920s, it became the site of the Hotel Royal.
In 1947, the property was leased to the USSR, and it served as the site of the Soviet — and later Russian — Embassy until the year 1999.
The mansion underwent extensive renovations in the 2000s, as part of development of the Sathorn Square office tower and the W Bangkok hotel, which now straddle the mansion on each side. It reopened in July 2015 as a restaurant and entertainment venue for the W Bangkok, known as "The House on Sathorn".