100 Park Avenue is a 36-story commercial office tower located at the address 100 Park Avenue, Midtown Manhattan, New York City, NY 10017. Constructed in 1949, the building was one of the first post-war office towers to rise on Park Avenue south of Grand Central Terminal and, at the time of its completion, was the tallest and most expensive post-war office building in New York City.
Architecture and Design: The original building was designed in a modernist style. Between 2007 and 2009, a major $72–$75 million renovation was completed by Moed de Armas and Shannon (MdeAS Architects). The renovation added a new unitized glass curtain wall on the Park Avenue facade and aluminum composite metal panels with punched windows on the north and south facades. A new double-height atrium lobby and glass storefronts were also created at street level. The building has approximately 825,000 to 905,000 square feet of leasable space.
Ownership and Management: The building is owned and managed by SL Green Realty Corp., a publicly traded real estate investment trust. In January 2026, SL Green and Rockpoint announced a joint venture for ownership of the property.
Certifications and Awards: The building has achieved LEED Gold certification, ENERGY STAR certification, BOMA 360 designation, WiredScore Platinum, and WELL Health-Safety Rating. It was awarded "International Building of the Year" by the Building Owners and Managers Association (BOMA) in 2009 and received the BOMA Atlantic Region and New York State Building of the Year awards for its renovation.
Notable Tenants: Major tenants include AECOM, AlphaSights, Alvarez & Marsal, Chop't (retail), and Valley National Bank (retail).
Location and Amenities: The building is located one block from Grand Central Terminal and two blocks from Bryant Park and the New York Public Library. Amenities include conference and meeting rooms, a cafe, lounges, a game room, wellness facilities, a golf simulator, and a personal training studio. The building features green roofs and infrastructure upgrades such as a new cooling plant and increased electric capacity.
