John Henry Hammond, a New York lawyer, banker and corporation director, married Emily Vanderbilt Sloane; in 1901 her father, William D. Sloane of W. & J. Sloane, purchased the 91st Street property from Andrew Carnegie and then transferred the property to Emily as a wedding present. Mrs. Hammond, an heiress to the Sloane and Vanderbilt fortunes, devoted much of her time to philanthropic activities including the restoration of the Theodore Roosevelt House at 28 East 20th Street.
The Hammond house is now occupied by the 9 East 91st Street Hospital. The five-story house with its impressive limestone facade harmonizes extremely well with the distinguished Landmarks buildings immediately to the west, the Otto Kahn and James Burden Houses. The boldly rusticated base is pierced by a high round-arched central entrance, flanked by arched windows. The entrance doors are fine examples of wrought iron. Rising above the base are three floors faced with smooth limestone, clearly defined at the edges by exceptionally wide quoins.