New York hardcore (also known as NYHC) is both the hardcore punk music created in New York City and the subculture and lifestyle associated with that music. The scene established many aspects that are fixtures of hardcore punk today, including its simplified name "hardcore", its hardcore skinhead and youth crew subcultures, the moshing style hardcore dancing, its association with street gangs and its prominent influence of heavy metal.
The scene experienced many distinct waves and deviations in style: early 1980s bands who directly outgrew the earlier punk scene including Agnostic Front, Reagan Youth and Kraut began the scene. In mid–1980s, the Cro-Mags, Leeway and Stormtroopers of Death embraced the influence of the nascent thrash metal genre, helping to pioneer crossover thrash. In mid-to-late 1980s, a reaction against this metal influence saw Youth of Today, Gorilla Biscuits and Bold established the youth crew subculture, which revived hardcore's punk–based roots. However, by the end of the decade, thrash metal's influence permeated the scene again establishing a new form, tough guy hardcore, played by Sick of It All, Breakdown, Madball and Killing Time. During the 1990s, the sound of New York hardcore largely diversified: Helmet, Quicksand and Life of Agony helped to establish the alternative metal genre, while Bulldoze (band) and 25 ta Life pioneered beatdown hardcore and Merauder All Out War and Vision of Disorder becoming prominent forces in metalcore. Furthermore Biohazard, Cro-Mags and Skarhead embracing influences from hip hop and H2O and CIV creating music indebted to pop music.