The mansion is a New York City designated landmark and, along with the Kahn House, is listed on the National Register of Historic Places.

The mansion's limestone facade is rusticated on its lowest two stories, with segmental archways and multiple entrances to the south and east.

The house has French-style interiors and is divided into front and rear sections, with an oval entrance hall connecting the floors.

[10] The townhouses on 11, 15, and 17 East 90th Street and the Spence School are located on the same block as the Carnegie Mansion, southeast of the Burden House.

[18] Ever since the government of the Soviet Union took over the Hammond House in the 1970s, the courtyard has served as a parking lot, which is closed off by a rolldown gate.

[21] The main entrance, on the eastern elevation,[19][13] was made of glass and iron and was accessed by a covered driveway, which functioned as a porte-cochère, or courtyard doorway.

[3][21] On the southern elevation, the second story has three square windows, which are flanked by console brackets that hold up the third-floor balcony.

[3][21] The fifth story is placed within a mansard roof and is set back from 91st Street, with dormer windows on the eastern elevation.

The entrance hall contains walls of Caen stone, while the grand staircase has marble treads and a wrought-iron balustrade.

On the ceiling of the oval stairway hall is a red, orange, and yellow mural of the arts,[17] which was painted by the muralist Hector d'Espouy.

Adjacent to the boudoir was Florence's bedroom, which originally had gray-blue walls, satin tapestries, and wall-mounted steel engravings.

On the same floor were James's bedroom, which had green hangings; a tile-and-marble bathroom; and a walk-in closet that doubled as his dressing room.

A small dining room on the same floor was painted in red and gold, with tapestries of the same color and inlaid marble sideboards.

[17][24] The ballroom is designed in the Louis XIV style,[17][31] with paneled violet-gray marble walls[17] and a decorative plaster ceiling.

[24][33] The music room, which one newspaper described as costing $60,000, had other decorative features such as tapestries, crystal chandeliers, paneled walls, and wooden floors in a herringbone pattern.

The top stories, originally used as bedrooms and living spaces, are used as the Convent of the Sacred Heart's offices and classrooms.

[24] In December 1898, the industrialist Andrew Carnegie bought all of the lots on Fifth Avenue between 90th and 92nd streets, with the intent of building his mansion on some of these plots.

[39][12] Carnegie sold four land lots on 91st Street to the businessman William Douglas Sloane in December 1900,[40][b] measuring 136 feet (41 m) wide.

[41] Soon after buying the lots, Sloane commissioned the architects Warren & Wetmore to design a house as a wedding present for Florence and James Burden,[42] who had been living at 8 East 69th Street since 1897.

[50] Early census figures for the Burden family are unavailable, but a National Park Service report indicates that James, Florence, and their three young children may have had at least 10 servants living with them.

[6] When Carnegie tried to split the adjacent parcel at 91st Street and Fifth Avenue and sell part of it to Lloyd Bryce in 1906, Sloane and his daughters all opposed the sale.

[58] During the 1910s and 1920s, the Burdens hosted several events at their house, such as musical dinners,[59] as well as debutante receptions for their daughter Shiela[60] and their niece Emily Hammond.

[67] Meanwhile, John Jacob Astor VI leased the Burden House in December 1933 after his engagement to Eileen Sherman Gillespie.

[69] Following their marriage later that year, Astor and French moved into the house in November 1934,[70] and they hosted their first major society event there, a supper dance, in December 1935.

[75] The auction included Belgian tapestries, carpets, and French busts, in addition to paintings such as a portrait of the Marquess of Normanby.

The house also contained various pieces of English, French, and Italian furniture, including a carved walnut table, Chippendale chairs and sofa, wooden urns, a foldable five-paneled screen, and six Louis XVI-style armchairs.

[13] One reporter wrote that "a veritable 'Berlin Wall' separates the mansions once owned by the Sloane sisters", the Burden and Hammond houses.

[89] The architecture firm of Buttrick White & Burtis was hired in the early 1980s to add a gymnasium, laboratories, and classroom space in the Burden and Kahn houses.

The project, which was estimated to cost $1.5 million, was funded in part from revenue generated by the Burden House's ballroom,[90] as well as from events such as tours and Christmas tree sales.

"[13] Architectural critic Henry Hope Reed Jr. wrote in 1961 that the Kahn, Burden, and Hammond houses were "the crown jewel of the block".