The Benjamin N. Duke House is at 1009 Fifth Avenue in the Upper East Side neighborhood of Manhattan in New York City.

[5][7] Historically, the house was part of Fifth Avenue's "Millionaires' Row", a grouping of mansions owned by some of the United States' wealthiest people.

[8] Historically, the Benjamin N. Duke House was one of four adjacent mansions at 1006 through 1009 Fifth Avenue that were developed by William W. and Thomas M. Hall and completed in 1901.

who worked nearly exclusively for William W. and Thomas M. Hall, designed many buildings on the Upper East Side in the early 20th century.

The doors are made of wrought iron and glass and are flanked by engaged columns and narrow windows on either side.

[18][19] On the ground story, the side pavilions (comprising the first, second, fourth, and fifth bays from west) have rectangular windows flanked by brackets.

[22] The wing at the eastern end of the 82nd Street facade is one bay wide and is clad with rusticated limestone blocks at its base.

The western part of the third floor is occupied by a rococo-style library with a red-marble mantel, as well as bookcase built into the walls.

[29] In 1995, the original residence was divided into three apartments, as well as a 250 sq ft (23 m2) room for the Duke family on the ground floor.

[10] In July 1899, the Halls hired Welch, Smith & Provot to design three five-story mansions at the southeast corner of Fifth Avenue and 82nd Street at a cost of $255,000 (equivalent to $9,339,120 in 2023).

[31] The New York City Department of Buildings granted the developers a single work permit for the three houses, occupying the lots at 1007–1009 Fifth Avenue.

[10] Contemporary sources initially reported that tobacco businessman James Buchanan Duke had acquired the house at 1009 Fifth Avenue, facing 82nd Street.

[27] It is not known why Benjamin Duke did not develop his own house, as he was worth $60 million at the time (equal to $2.2 billion in 2023).

[9] In late 1906, James met cotton heiress Nanaline Holt Inman at a party in his brother's house.

James married Nanaline eight months later, in July 1907, and bought a plot at the northeast corner of Fifth Avenue and 78th Street, where he intended to build a mansion.

[40][41] James is recorded as having lived in the house by early 1908, when he gave testimony from his bedroom as part of an antitrust lawsuit that the federal government had brought against the American Tobacco Company.

[4][37] The same year, Benjamin built his own house at Fifth Avenue and 89th Street on the future site of the Solomon R. Guggenheim Museum.

[9] Mary Lillian Duke bought an estate in Durham, North Carolina, in 1935 and began spending increasing amounts of time there.

[13] Richard Peck of The New York Times wrote that the house's landmark designation only covered a single site and "has not preserved the block against a high-rise of two-and-a-half-room apartment units".

[57] That year, a state judge ruled that the LPC was required to at least host public hearings for the proposed district.

[62][63] Ultimately, Goldman and Zucker's original plan fell through, and Peter Kalikow leased the apartment-house site.

Joseph Fiebiger, whose grandfather had created the original wrought-iron decorations, was hired to rebuild the corroded copper roof.

[24] The contractors used a biodegradable paint remover on the facade, and they treated the wrought-iron window guards with polyurethane, epoxy, and an organic zinc mixture to prevent the iron from rusting.

The project also included renovating the basement into doctors' offices, raising the roof to create a seventh story, and splitting the interior into three floors.

[25] Because of its high asking price, the house's brokers only offered tours to potential buyers after checking their bank accounts.

[66] Sapir placed the mansion for sale in January 2010 for $50 million,[26][28] and Paula Del Nunzio of brokerage firm Brown Harris Stevens was hired to market the building under an exclusive listing agreement.

[72][73] Sapir finalized his sale of the building in July 2010; sources initially reported that a Russian businessman had bought the house.

[71][74] Mexican telecom magnate Carlos Slim, at the time the richest person in the world, was reported as the buyer, having paid $44 million.

[26] Brown Harris Stevens sued Sapir for breach of contract in August 2010, claiming that Sapir had tried to avoid paying a broker's commission to Del Nunzio by secretly negotiating directly with Slim, then waiting until Del Nunzio's contract had expired before finalizing the sale.

[9] The New York Observer wrote in 2015 that the building was "a Beaux-Arts confection eight stories tall with a corner orientation that offers that most rare of townhouse qualities—good light".