Depends who classifies. For weather stations the Northeast includes all New York, Connecticut, and points North. may also include Penn and New Joisey.
Agree with Cuda...depends. Some say NY NJ (and even PA) while others add Delmarva (and even DC end WV). From a surfing perspective, I sorta agree with SI. Even putting SE NC in SE region and NY on NE.
If there's a York, a Jersey and a Hampshire in England, and New York and New Hampshire are in New England, why isn't New Jersey? Southeast should be FL to SC. Mid-Atlantic should be NC to DE. New England should be NJ to ME.
btw, New York is not considered to be part of New England from a geographical/cultural standpoint. https://www.quora.com/Why-is-New-York-not-considered-to-be-part-of-New-England
You're right... Sig. But Upstate NY is New England-ish... sort of... right? With all those stone walls... and their affinity for chowder and whatnot...