525 Lexington Avenue (also FOUND Study Turtle Bay; formerly the Shelton Hotel, Shelton Towers Hotel, Halloran House, and the New York Marriott East Side) is a student dormitory and former hotel building at 525 Lexington Avenue in Midtown Manhattan, New York City. The 34-story, building was designed by Arthur Loomis Harmon in a classical style and was developed by James T. Lee, grandfather of First Lady Jacqueline Bouvier Kennedy Onassis. It was constructed between 1922 and 1923 as the Shelton Hotel, an apartment hotel. The Marriott East Side, one of several large hotels developed around Grand Central Terminal as part of Terminal City, became a New York City designated landmark in 2016.

The building contains setbacks to comply with the 1916 Zoning Resolution; at the time of its construction, the Shelton was quoted as the world's tallest hotel. The first two stories of the facade are clad with limestone, while the upper stories are faced with grayish-brown brick, interspersed with terracotta and limestone trim. When it opened, the hotel featured numerous amenities similar to those in a clubhouse, such as a gymnasium, a bowling alley, Victorian-style Turkish baths, a swimming pool, a barber, squash courts, and billiard tables. The upper stories originally contained 1,200 rooms, which was decreased to about 650 rooms in the late 1970s, as well as outdoor terraces on the 15th and 31st floors. The Shelton Hotel was widely praised by architectural critics upon its completion. Its design has been cited as an influence for that of other structures, such as the Empire State Building.

Lee acquired the site in 1922 from the International Sporting Club, which had unsuccessfully attempted to build a clubhouse there. The hotel was completed in January 1924 as a men-only hostelry and opened to women later that year; it attracted tenants such as Alfred Stieglitz and Georgia O'Keeffe. The New York Life Insurance Company acquired the hotel in 1935, and the Knott Management Corporation took over the hotel's operation, buying it in 1946. The hotel was sold multiple times in the 1950s. Sol Goldman and Alex DiLorenzo Jr. bought the hotel in the 1960s and leased it to Stanley Stahl, who closed the hotel in May 1971. Tishman Realty & Construction planned to build a skyscraper on the site in the 1970s but canceled its plans after several holdout tenants refused to relocate. The contractor Edward Halloran acquired the hotel in 1976 and renovated it into the Halloran House, a Howard Johnson's hotel. Marriott Hotels & Resorts took over the hotel in 1990 and operated it until 2020, when the hotel closed as a result of the COVID-19 pandemic. Hawkins Way Capital and Värde Partners bought the building in early 2023 and renovated it into a student housing facility, FOUND Study Turtle Bay, which opened that September.

Site 525 Lexington Avenue is on the eastern side of Lexington Avenue, on the southeast corner with 49th Street, in the Midtown Manhattan neighborhood of New York City. It sits on the western portion of a city block bounded by Lexington Avenue to the west, 49th Street to the north, Third Avenue to the east, and 48th Street to the south. The hotel occupies an irregular land lot with an area of ; the eastern portion of the lot extends southward to 48th Street. The site has a frontage of on Lexington Avenue, on 49th Street, and wide on 48th Street.

525 Lexington Avenue wraps around another building at the northeast corner of 48th Street and Lexington Avenue (which was completed around 2009), and it abuts a public plaza to the southeast. When the Shelton was constructed, the corner lot contained a three-story brick building, which was destroyed in 1939. The hotel is across from 277 Park Avenue to the southwest, the InterContinental New York Barclay Hotel and 299 Park Avenue to the west, the Waldorf Astoria New York to the northwest, and the Lexington Hotel NYC to the south. The Shelton was part of "Hotel Row", a collection of hotels developed along Lexington Avenue in the early 20th century. The surrounding section of Lexington Avenue from 42nd to 52nd Street did not experience significant development until the late 19th century, when row houses and tenements, made of brick and brownstone, were developed in the area.

Architecture 525 Lexington Avenue was designed by Arthur Loomis Harmon, who went on to design the Empire State Building and 500 Fifth Avenue. The hotel was originally known as the Shelton, an apartment hotel, and was developed by James T. Lee, grandfather of Jacqueline Kennedy Onassis. The hotel contains elements of the Lombard Revival style, although Harmon wanted to avoid clear allusion to any specific architectural style, saying that "the masses of such modern buildings have no architectural precedence". Christopher Gray of The New York Times wrote that Harmon "covered the mass with irregular yellowy-tan brick, roughened as if centuries old, and for details, drew from Romanesque, Byzantine, early Christian, Lombard and other styles." The hotel's developer described the building as being designed in a "North Italian Romanesque or Early Christian" style.

Form

The hotel building contains setbacks to comply with the 1916 Zoning Resolution; it was one of the first major hotels in New York City to be developed after the resolution was enacted. At the time of its construction, the Shelton was also quoted as the world's tallest hotel; modern sources cite the hotel as being 387 feet (118 m) tall, although a source from 1932 gave an alternate height of . The building is variously cited as being 31, 32, 34, or 35 stories tall. This discrepancy arises from the fact that the hotel's floor numbering system does not have a thirteenth floor, as well as the fact that there is a three-story mechanical penthouse above the primary 31-story roof. Including the penthouse, the hotel has a total of 34 floors.

According to art historian Anna C. Chave, Harmon preferred that the hotel's setbacks "be boldly articulated in architectural form, not camouflaged by ornamentation". To maximize the size of the public amenity space, the lowest two stories of 525 Lexington Avenue occupy the entire site. On the first 15 stories of the hotel, a wing runs south to 48th Street from the center of the main structure's southern elevation. The wing on 48th Street contains a setback on its rear above the first story, as well as on its front above the second story. At the 3rd story, the eastern elevation sets back into an elongated light court, giving the building a roughly U-shaped plan. The northern elevation on 49th Street and the western elevation on Lexington Avenue also have light courts, which are shallower and are flanked by projecting pavilions. Another light court exists on the eastern elevation.

The hotel has further setbacks at the 15th and 21st floors; the main roof is above the 31st floor. To comply with the 1916 Zoning Resolution, the top stories of the hotel only occupy one-quarter of the entire lot. The hotel is topped by a set-back penthouse with a pyramidal hip roof.

Facade All four elevations of the hotel's facade are visible from the street and are accordingly decorated. The first two stories of the facade are clad with limestone. The upper stories are faced with grayish-brown brick, interspersed with terracotta and limestone trim. The third through 14th stories, and the 16th to 30th stories, have windows that illuminate guestrooms inside. The 15th and 31st stories are designed in a different manner because these stories originally contained amenity areas.

The facade is divided vertically into multiple bays, which alternately project from the facade or are recessed from it. On the upper stories, projecting bricks were arranged both in vertical lines and in random patterns. Harmon, seeking to emphasize the hotel's height, avoided including horizontal lines in the hotel's design where possible. The facade's design followed the principle of entasis, bulging slightly outward so as to not give the impression that the hotel was sagging, The lower stories were sloped slightly inward, further emphasizing the building's height. The original design was modified significantly in 1935. The modern-day facade, which dates to a 1977–1978 renovation, is similar to the original design but has additional doorways and windows.

Base

The 49th Street and Lexington Avenue elevations of the facade have double-height arcades at the base. The Lexington Avenue facade contains a loggia of five arches in the center of the facade, as well as a glass-and-metal canopy that curves outward. The arches are flanked by pedestals with lion heads, which support Corinthian columns. Above the columns are impost blocks, which contain depictions of readers and athletes carved in relief, as well as molded archivolts and gargoyles. In addition, a cornice with corbels runs horizontally above the second floor, topped by a parapet that contains reliefs of masks. The three center archways lead into the lobby and are surrounded by doorways with Renaissance-style arabesques. There are arched niches in between each of the center doorways. On the second story, each of the five center bays contains a pair of arched windows.

The Lexington Avenue entrance is flanked by three-bay-wide projecting pavilions. The first story originally had rectangular window openings, though one window in each pavilion has since been replaced by a doorway. The southernmost bay of the south pavilion contains an entrance with a projecting granite doorway. At the second floor, the center bay of each pavilion contains a pair of arched windows and a balcony supported by brackets (these bays originally contained French windows). The other bays have simple rectangular windows on the second floor, above which are relief panels with scrolls and wreaths, which are inset into the facade. A cornice, with corbels shaped like masks and flowers, runs above the second story of each pavilion. Over the years, objects such as air-conditioner openings, storage cabinet, a security camera, and flagpoles have been added at the base.

The 49th Street facade is similar in arrangement to that along Lexington Avenue, with a recessed arcade flanked by pavilions. The arcade is six bays wide; the westernmost bay of the arcade contains an entrance. There are awnings above the first-story windows in each bay of the arcade, and a low iron railing runs in front of the arcade's first-floor windows. Above the first story, the arcade contains are chevron patterns consisting of light and dark stone. The eastern pavilion contains square-headed windows on its mezzanine level, while the windows on the first and second story have been sealed. A stone balustrade runs above the arcade's second story and is decorated with quatrefoil tracery.

On the 48th Street wing, the southern elevation is clad with limestone in multiple hues. At the first and second stories, the facade of the wing is divided into three bays; the center bay is divided into four windows, while the side bays have two windows each. On the first story, the center window is topped by a lunette, and there is a door in the westernmost bay; all of the windows have tracery and stone mullions. The wing's second story contains a terrace recessed behind the windows on that story. The main section of the building, closer to 49th Street, contains arched windows on its southern elevation at the second story; these windows originally illuminated the hotel's library. A concrete-clad annex, consisting of the first story and mezzanine, extends into the courtyard at the hotel's southeast corner; this annex contains ventilation grates and HVAC equipment on its roof.

Upper stories