this really only applies to New York, as New York City is in the bottom little bit of the state’s southern nubbin and the rest of the state is commonly called “Upstate New York” since when people outside the northeast refer to New York, they’re talking about New York City, rather than the state of New York. thus Upstate New York was shortened to Upstate. (it seems to hold that most people i know who grew up in the northeast call New York City “NYC” rather than what i used growing up which was “New York.”

I am an american, I grew up in a state in the south west, no one ever used the term “going upstate” for anything because there was no such place to go.

I guarantee you only see dialog such as this in media set in NYC.