John Henry Hammond House

The John Henry Hammond House is a mansion at 9 East 91st Street in the Carnegie Hill section of the Upper East Side of Manhattan in New York City. Designed by architects Carrère and Hastings in the Italian Renaissance style, it was completed by 1906 as the residence of lawyer John Henry Hammond and his wife Emily Vanderbilt Sloane Hammond. The Russian Federation owns the house and has used it as the Consulate General of Russia to New York City since 1994. The mansion is a New York City designated landmark.

The Hammond House is five stories high, with its fifth story set back from the facade. The mansion's limestone facade is rusticated on its lowest two stories, and each corner of the building has vertical stone quoins. The second story of the facade is designed like a piano nobile, while the upper stories have progressively smaller windows. The rooms were designed in the Louis XVI style, with features such as elevators and a squash court. When the house was built, the ground (or first) floor had a "T"-shaped entrance hall, a billiards room, a dining room, and a breakfast room. The reception rooms on the second floor—which included a ballroom, library, and music room—could accommodate hundreds of guests. The third and fourth floors were used as bedrooms. There is also an attic, which originally contained female servants' quarters and an infirmary, and a basement, with male servants' quarters.

Andrew Carnegie purchased the site in 1898 to protect the value of his nearby mansion. William D. Sloane, of the W. & J. Sloane furniture family, acquired the site from Carnegie in 1901 and commissioned the Hammond House and the adjacent James A. Burden House for his daughters. The house served as the Hammond family's home from 1905 to 1946, when the eye surgeon Ramón Castroviejo bought the house and slightly modified the interior. He used the house as his office and residence while operating an eye hospital on the top floors. The Soviet government bought the house in 1975 and renovated it, but the consulate's opening was delayed due to an agreement with the U.S. After the U.S. expelled Soviet diplomats in 1980, the house was abandoned and fell into disrepair. It was renovated from 1992 to 1994, allowing it to serve as the Russian consulate to New York City.