Nine people died when a tour helicopter and a small private airplane collided over the Hudson River in Hoboken, New Jersey.

On August 8, 2009, at 11:53 a.m. (15:53 UTC), nine people died when a tour helicopter and a small private airplane collided over the Hudson River near Frank Sinatra Park in Hoboken, New Jersey, United States. The aircraft were in an area known as the "Hudson River VFR Corridor", which extends from the surface of the river to altitudes of 800 to 1,500 ft at various locations along the Hudson River in the immediate area of New York City. Within this corridor, aircraft operate under visual flight rules (VFR), under which the responsibility to see and avoid other air traffic rests with the individual pilots rather than with the air traffic controller (ATC).

The Hudson River, historically the North River, is a 315-mile (507 km) river that flows from north to south largely through eastern New York state. It originates in the Adirondack Mountains at Henderson Lake in the town of Newcomb, and flows south to the New York Bay, a tidal estuary between New York and Jersey City, before draining into the Atlantic Ocean. The river marks boundaries between several New York counties and the eastern border between the U.S. states of New York and New Jersey. The lower half of the river is a tidal estuary, deeper than the body of water into which it flows, occupying the Hudson Fjord, an inlet that formed during the most recent period of North American glaciation, estimated at 26,000 to 13,300 years ago. Even as far north as the city of Troy, the flow of the river changes direction with the tides.

Hoboken is a city in Hudson County in the U.S. state of New Jersey. Hoboken is part of the New York metropolitan area and is the site of Hoboken Terminal, a major transportation hub. As of the 2020 United States census, the city's population was 60,419, an increase of 10,414 (+20.8%) from the 2010 census count of 50,005, which in turn reflected an increase of 11,428 (+29.6%) from the 38,577 counted in the 2000 census. The Census Bureau's Population Estimates Program calculated a population of 57,010 for 2023, making it the 708th-most populous municipality in the nation. With more than 42,400 inhabitants per square mile (16,400/km²) in data from the 2010 census, Hoboken was ranked as the third-most densely populated municipality in the United States among cities with a population above 50,000. In the 2020 census, the city's population density climbed to more than 48,300 inhabitants per square mile (18,600/km²) of land, ranked fourth in the county behind Guttenberg, Union City and West New York.