State police said the crash occurred at around 11:30 a.m. on Blackberry Hill Road in Somers, just south of Somers High School and opposite Reis Park.
The boy killed has been identified as Reece Ferrara of Somers.
The ATV struck a concrete mailbox pillar, ejecting Ferrara from the vehicle, according to state police. He was transported to Westchester Medical Center where he was later pronounced dead.
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