The Andrew Carnegie Mansion is a historic house and a museum building at 2 East 91st Street, along the east side of Fifth Avenue, on the Upper East Side of Manhattan in New York City. The three-and-a-half story, brick and stone mansion was designed by Babb, Cook & Willard in the Georgian Revival style. Completed in 1902 for the industrialist Andrew Carnegie, his wife Louise, and their only child Margaret, it served as the family's residence until 1946. Since 1976, the house has been occupied by the Cooper-Hewitt Museum, part of the Smithsonian Institution. The mansion is internally connected to two townhouses at 9 East 90th Street and 11 East 90th Street, both of which are part of the Cooper-Hewitt.

The Upper East Side, sometimes abbreviated UES, is a neighborhood in the borough of Manhattan in New York City, bounded approximately by 96th Street to the north, the East River to the east, 59th Street to the south, and Central Park and Fifth Avenue to the west. The area incorporates several smaller neighborhoods, including Lenox Hill, Carnegie Hill, and Yorkville. Once known as the Silk Stocking District, it has long been the most affluent neighborhood in New York City.