The Catherine Auchincloss Mansion, listed at $13,500,000 million, epitomizes the grandeur and elegance of Park Avenue. This historic residence boasts 18 rooms, including 6 bedrooms, an additional staff bedroom, and 7 bathrooms, spread across 8,000 square feet. It features 6 working fireplaces, an elevator, a gym with a sauna, and a game room/art studio with a 20-foot-high skylight. Originally constructed in the 1870s as a brownstone, the mansion underwent a significant transformation in the early 1900s when Andrew Agnew purchased it for his daughter Catherine and her husband Edgar Auchincloss. The mansions illustrious history includes Catherines residency until 1950 and a familial connection to Jacqueline Kennedy Onassis through Hugh Auchincloss, Catherine's nephew and stepfather to the former First Lady. Entering the mansion, one is greeted by a grand full-width stone foyer and a stately reception hall featuring a sweeping staircase. The ground floor includes three staff rooms, two bathrooms, a laundry room, and a kitchenette. The parlor floor, designed as a piano nobile, stretches 2,000 square feet and includes a 90-foot enfilade of four grand entertaining rooms with 14-foot ceilings, a large gallery, and a living room with tall arched windows. The baronial dining room, adorned with original leaded glass windows, and the spacious eat-in kitchen with east-facing double height windows further enhance the mansion's charm. The third floor houses the luxurious primary suite, with a large windowed dressing room, separate walk-in closet, windowed master bath, and a working fireplace. An original wood-paneled library with a fireplace is also located on this floor. The fourth floor comprises two additional bedrooms with working fireplaces, a gym and sauna. It also features a 300 square foot sunny terrace with city views. The fifth floor features two more bedrooms, one of which is currently used as a large game room/art studio with a striking 20-foot-high north-facing skylight. This meticulously renovated mansion (updated 2022-2024) seamlessly blends historic architectural elements with modern luxury offering an unparalleled living experience. Its rich provenance and prime location on Park Avenue make the Catherine Auchincloss Mansion a rare and distinguished residence, epitomizing New York Citys elites timeless elegance and refined lifestyle.