Henry Janeway Hardenbergh was an American architect, best known for his hotels and apartment buildings. Hardenbergh was born in New Brunswick, New Jersey, of a Dutch family, and attended the Hasbrouck Institute in Jersey City. He apprenticed in New York from 1865 to 1870 under Detlef Lienau, and, in 1870, opened his own practice there.
He obtained his first contracts for three buildings at Rutgers College in New Brunswick, New Jersey—the expansion of Alexander Johnston Hall (1871), designing and building Geology Hall (1872) and the Kirkpatrick Chapel (1873)—through family connections. Hardenbergh's great-great grandfather, the Reverend Jacob Rutsen Hardenbergh, had been the first president of Rutgers College from 1785 to 1790, when it was still called "Queen's College".
He then got the contract to design the "Vancorlear" on West 55th Street, the first apartment hotel in New York City, in 1879. The following year he was commissioned by Edward S. Clark, then head of the Singer Sewing Machine Company, to build a housing development. As part of this work, he designed the pioneering Dakota Apartments in Central Park West, novel in its location, very far north of the centre of the city.
Subsequently, Hardenbergh received commissions to build the Waldorf (1893) and the adjoining Astoria (1897) hotels for William Waldorf Astor and Mrs. Astor, respectively. The two competing hotels were later joined together as the Waldorf-Astoria, which was demolished in 1929 for the construction of the Empire State Building.
Hardenbergh lived for some time in Bernardsville, New Jersey and died at his home in Manhattan, New York City on March 13, 1918. He is buried in Woodland Cemetery, in Stamford, Connecticut.