I'm from Jersey, so we don't really have much local slang, per se. However, we do have things and random crap we like to talk about that are relatively unique to our state, or just plain odd.
One thing everyone in our state likes to joke about, is tolls. You have to pay like 2 dollars to leave, but you can get into the state for free from pretty much anywhere, so we all joke that Jersey is so bad you have to pay to escape.
Something we do a lot is swap out the t's in words for d's, so sometimes it gets confusing.
We are called the Garden State, yet there are basically no gardens. Sure, we have farms like any other state, but literally no one has a garden.
PUBLIC TRANSPORT. Unless you live up north like in Bergen county or in the city, GOOD LUCK GETTING ANYWHERE WITHOUT A CAR! We have to drive almost 1.5 hours to get to a train station or bus stop, and even then it sucks. And I don't live in the middle of nowhere, I'm in a pretty populated area. And the train and/or bus is never actually on time either. It always is ridiculously late, or ridiculously early, there is literally no compromise.
DEER. SO MANY DEER.
Funny vandalism. I don't know about you, but every Christmas, without fail, people spray paint red noses on the deer silhouettes for those "Look out, deer crossing!" signs. We also do weird things when decorating for the holidays. Like decking out bulldozers and cars in christmas lights.
Going down to the boardwalk. So many people do it every year, and honestly, it's really cool experience. Almost everyone in Jersey has gone to the boardwalk at least once in their lives.
DID I MENTION THE DEER? THOSE BUSH KILLING CAR CRASHING MAILBOX DESTROYING OVERPOPULATING FEARLESS BASTERDS!!!!
Beachballs. I don't know why, but you can buy a beach ball literally anywhere, at any time of the year. And also random small animal plushies. And cheap candy/mints are in the checkout lines of every, and I mean EVERY store.
Italian places. These seem to make up most restaurants. I mean, sure there are plenty of diners and other places, but why do we need so MANY Italian places????? Does it cure the plague or what????