Coney Island is a neighborhood and entertainment area located in the southwestern section of the New York City borough of Brooklyn. It sits on the western portion of the Coney Island peninsula, which extends into Lower New York Bay with Sheepshead Bay to its northeast and Gravesend Bay to its northwest. The area is bounded by Brighton Beach to the east, Lower New York Bay to the south and west, and Gravesend to the north. Administratively, it forms part of Brooklyn Community District 13 and is patrolled by the 60th Precinct of the New York City Police Department.

The origin of the name Coney Island is disputed, with theories ranging from Dutch settlers to Native American tribes. The area was originally part of the colonial town of Gravesend, where Anthony Janszoon van Salee acquired land in 1639 and Guysbert Op Dyck received a patent for Conyne Island in 1644. By the mid-19th century, it had become a seaside resort, and by the late 19th century, amusement parks were built there. The attractions reached a historical peak during the first half of the 20th century before declining after World War II. The Coney Island Cyclone roller coaster, opened in 1927, was declared a New York City Landmark in 1988 and placed on the National Register of Historic Places in 1991.

The neighborhood includes the subsection of Sea Gate and is part of the larger Coney Island peninsula, which also comprises Brighton Beach and Manhattan Beach. The area features manmade structures to maintain its shape, including the Riegelmann Boardwalk built in 1922–1923 and numerous groynes holding sand in place. Notable sites include the Wonder Wheel, offering views of Manhattan, and Kaiser Park and Coney Island Creek Park on the northwest side. The amusement park area is known for its thrill rides, though it is surrounded by a high concentration of public housing projects that contribute to a perception of seedy character.

Coney Island is ethnically diverse, with Brighton Beach home to the largest Russian-speaking community outside the former USSR. Visitors can enjoy shashlik and vodka along the boardwalk, while Sheepshead Bay offers fishing piers and restaurants for Italian, Jewish, Chinese, and Russian immigrants. Gravesend, part of the broader area, contains the oldest English settlement in New York and features Syrian Orthodox Jewish neighborhoods with distinctive architecture. The area also includes small Chinese neighborhoods with Vietnamese restaurants and large graveyards visible from the F subway line.

The population was 24,711 as of 2010, though the neighborhood had around 32,000 residents as of the 2020 United States census. The poverty rate is 27%, slightly higher than the city average. The area has a humid subtropical climate with hardiness zone 7b and is sinking at approximately 2.6 millimeters per year due to land reclamation. It is well served by the New York City Subway, with D, F, N, and Q trains reaching Coney Island-Stillwell Avenue, and local bus routes providing additional access to the entertainment and residential districts.