Wikipedia says:
The prominent architect Cyrus L.W. Eidlitz, son of the influential New York architect Leopold Eidlitz, was commissioned to design the building. Eidlitz had designed a number of landmark buildings throughout the country, including Dearborn Station in Chicago, Buffalo & Erie County Public Library, St. Peter’s Church in the Bronx, and Bell Laboratories Building in Manhattan.
Construction was begun in early 1895 and completed 18 months later at a total cost of $584,700. The House was built in the neoclassical style, from Indiana limestone. The façade included elements of the Doric order on the bottom three floors, Ionic columns framing the fourth floor windows, and Corinthian pilasters on the fifth floor, creating a historicist “composite” of classical architecture.
The new House was considerably larger and grander than its precursors: it stood six stories tall; included a meeting hall with a seating capacity of 1,500; a reception hall with a standing capacity of 1,500; a library of over 50,000 volumes, and three additional floors of offices. The entrance hall and first floor stairways were constructed of marble, and the second floor hallway, reception hall, and meeting hall of granite, marble, and mahogany.
The Association opened the doors of its new House on October 8, 1896, with a gala of several thousand guests. The New York Times described it as “one of the most interesting and successful works of recent architecture…a work having the classical qualities of simplicity, purity, and serenity in a high degree.” [3]
The House was named a New York City Landmark in 1966, and named to the National Register of Historic Places in 1980.