The Alexander Hamilton U.S. Custom House (originally the New York Custom House) is a government building, museum, and former custom house at 1 Bowling Green, near the southern end of Manhattan in New York City, New York, United States. Designed by Cass Gilbert in the Beaux-Arts style, it was erected from 1902 to 1907 by the government of the United States as a headquarters for the Port of New York's duty collection operations. The building contains the George Gustav Heye Center museum, the United States Bankruptcy Court for the Southern District of New York, and the New York regional offices of the National Archives. The facade and part of the interior are New York City designated landmarks, and the building is listed on both the New York State Register of Historic Places and the National Register of Historic Places (NRHP) as a National Historic Landmark. It is also a contributing property to the Wall Street Historic District, listed on the NRHP.

The Custom House is a seven-story steel-framed structure with a stone facade and elaborate interiors. The exterior is decorated with nautical motifs and sculptures by twelve artists. The second through fourth stories contain colonnades with Corinthian columns. The main entrance consists of a grand staircase flanked by Four Continents, a set of four statues by Daniel Chester French. The second-story entrance vestibule leads to a transverse lobby, a rotunda, and offices. The rotunda includes a skylight and ceiling murals by Reginald Marsh. The George Gustav Heye Center, a branch of the National Museum of the American Indian, operates on the ground and second stories, while the upper stories contain U.S. government offices.

The building was proposed in 1889 as a replacement for the previous New York Custom House at 55 Wall Street. Because of various disagreements, the Bowling Green Custom House was not approved until 1899; Gilbert was selected as architect following a competition. The building opened in 1907, and the murals in the rotunda were added in 1938 during a Works Progress Administration project. The United States Customs Service moved out of the building in 1974, and it remained vacant for over a decade until renovations in the late 1980s. The Custom House was renamed in 1990 to commemorate Alexander Hamilton, one of the Founding Fathers of the United States and its first Secretary of the Treasury. The Heye Center opened in 1994.

The Alexander Hamilton U.S. Custom House occupies a trapezoidal plot bounded by Bowling Green to the north, Whitehall Street to the east, Bridge Street to the south, and State Street to the west. The Whitehall Street and State Street elevations are 300 feet (90 m) wide; the main elevation on Bowling Green is 200 feet (60 m) wide; and the rear elevation on Bridge Street is 290 feet (88 m) wide. As of 2023^[update], a concrete retaining wall measuring 16 feet (4.9 m) deep was being built around the building. Nearby buildings include the International Mercantile Marine Company Building and the Bowling Green Offices Building to the northwest, 26 Broadway to the northeast, 2 Broadway to the east, and One Battery Park Plaza to the south.

There are entrances to two New York City Subway stations immediately outside the Custom House. An entrance to the Whitehall Street station is adjacent to the eastern side of the building, while an entrance to the Bowling Green station is to the north. The building occupies the site of Fort Amsterdam, constructed by the Dutch West India Company to defend their operations in the Hudson Valley. The Dutch colony of New Amsterdam, the precursor to modern-day New York City, was developed around the fort. Bowling Green, immediately to the north, is the oldest park in New York City. The Government House occupied the site in the late 18th century before its demolition in 1815. The houses of several wealthy New Yorkers were subsequently developed at that location.

The Alexander Hamilton U.S. Custom House is seven stories high with a stone facade and an interior steel frame. It was designed by Cass Gilbert in the Beaux-Arts style. The design is similar to those of previous custom houses in New York City, namely Ithiel Town's Federal Hall at 26 Wall Street and Isaiah Rogers's Merchants' Exchange building at 55 Wall Street.

The building's design incorporates Beaux-Arts and City Beautiful planning principles, combining architecture, engineering, and fine arts. Gilbert had written in 1900 about his plans for a wide-ranging, site-specific decorative program, which would "illustrate the commerce of ancient and modern times, both by land and sea". Sculptures, paintings, and decorations by well-known artists of the time, such as Daniel Chester French, Karl Bitter, Louis Saint-Gaudens, and Albert Jaegers, embellish various portions of the interior and exterior.

U.S. Customs and Border Protection owns the Custom House. The building houses the Smithsonian Institution, the National Archives and Records Administration, the United States Bankruptcy Court for the Southern District of New York, and offices for the United States Department of Transportation.