The Mrs. William B. Astor House was a mansion on the Upper East Side of Manhattan, New York City, at 840-841 Fifth Avenue on the northeast corner of 65th Street, completed in 1896 and demolished around 1926.

From the great hall, guests could enter the Adam style reception room, where they were received, on formal occasions, by their hostess standing beneath her own portrait by Carolus-Duran.

The room’s black-and-white marble-tiled floor was covered with polar-bear rugs, all centered on the marble stoned chimney piece, the mantle of which displayed vases.

At one end of the ballroom was a huge marble chimneypiece rising to the ceiling; this was decorated with two sculptures of male caryatids supporting a painted panel of a gala at the Palace of Versailles.

At the opposing end, at second floor level, was a minstrels' gallery, where a wall of Chinese screens blocked the musicians' view of the room.

At the centre of the ballroom was placed a round, red velvet ottoman constructed around a large marble urn; matching this, arranged around the room were canapés and chairs.